Speculation On the Origin of Series - Zoan Taxonomy (pt 1)

Just how closely related do two Zoans need to be in order to be counted as the same series?

  1. Tokiro Oumaga
    Hello everyone. It has been quite a long time since my last post, and for that I apologize. I have been very busy with my personal life and unfortunately had no inspiration for topics to post about, but recently inspiration struck.

    When I was a kid, I was told "dogs are canines and wolves are lupines. They look alike, but they're completely different animals." I always accepted this because an adult told me, and surely adults are always right.

    I remembered that little nugget of wisdom a short while ago and, being much more skilled in critical thinking than I was a child, I decided to dig into that a little bit deeper. As it turns out, wolves are, in fact, classified as Canis lupus; in other words, canines. What's more, not only are dogs and wolves both canines, they're so closely related that there's actually debate within the scientific community as to whether dogs should be classified as a subspecies of wolves, Canis lupus familiaris, or their own independent species, Canis familiaris.

    Upon learning this, it occurred to me that it is appropriate for the Dog-Dog series of Zoan Fruit to have a Wolf Model. From there, I got to thinking, what about the other Zoans? Are they all organized completely appropriately like the Wolf Model is, or are they misplaced like I thought the Wolf Model was before I learned this?

    Jumping off of this, I researched the taxonomic ranks of every known Zoan Fruit, both canon and non-canon, to determine what, if any, are the qualifications for any given Zoan series. Once we have our criteria down, we should be able to do two things:
    1. Determine what series the unnamed Zoans are models of
    2. Conjecture what future animals could appear in the known series or get their own new series
    Before we begin, here's a brief refresher on taxonomy for anyone who hasn't taken a biology class recently.

    Taxonomic Rank.png

    All life is categorized based on how closely related any given type of organism is to others. Domains are the biggest, as there are only three categories: Archaea, Bacteria, and Eukarya. Eukarya is divided into five Kingdoms: Plantae, Fungi, Chromista, Protista, and most importantly for our purposes, Animalia. Kingdoms are then divided into Phyla, Classes, Orders, Families, Genera, and finally Species, the most specific category in that it only actually includes one type of organism. Of course, Species can be divided into subspecies and breeds, but we'll cover that in a bit.

    With that out of the way, let's get started.

    Since we're already on the topic, let's begin with the Dog-Dog series. In this series, we have five known Models, four of which are canon:

    Dachshund Model.png
    • Dachshund, a breed of Canis familiaris
    Jackal Model.png
    • Jackal, of Genus Canis, though which species is unclear. Given that it's based on Anubis, it's probably not even actually a true jackal at all, but the African golden wolf, Canis anthus, but we won't fault it for that since it's Canis either way
    Wolf Model.png
    • Wolf, Canis lupus
    Nine Tailed Fox Model.png
    • Nine-Tailed Fox, most likely a Mythical variant of the red fox, and thus Vulpes vulpes. Though not Genus Canis like the previous Dog-Dog models, foxes are in the same Family as the others, Canidae, which effectively translates to "dog-like"
    Bakedanuki Model.png
    • Bake-danuki, a Mythical variant of the tanuki, and thus Nyctereutes procyonoides viverrinus (that's a heck of a mouthful) of Family Canidae
    Since clearly Canis familiaris is fair game for the Dog-Dog series, there are two unnamed Zoans that are unquestionably models of this series:

    Dalmation Model 2.png
    • Dalmatian, a breed of Canis familiaris
    Chihuahua Model.png
    • Chihuahua, also a breed of Canis familiaris
    Currently, those are the only unnamed Zoans that fit, but what about future Zoans? While stopping at just the canines of Genus Canis would have made perfect sense, Oda seems to have decided to extend the Dog-Dog series to the canids of Family Canidae, presumably for the sake of parsimony (probably to avoid having too many series or standalone models). This means that we could potentially see coyotes, dholes, dingoes, bush dogs, maned wolves, fennec foxes, and a whole host of other non-dog/wolf/fox animals that were arbitrarily given those names.

    Up to this point, we haven't had any evidence to confirm or deny this, but there is one more step-up we could go with the Dog-Dog series: Caniformia, a suborder of Order Carnivora, meaning dog-shaped. Basically, this means animals that have similar evolutionary adaptations to dogs and without actually being a part of Family Canidae, such as the shape of their snouts, number of teeth, non-retractable claws, etc. This definition would expand the Dog-Dog series to include bears, raccoons, badgers, skunks, red pandas, weasels, otters, seals, walruses, etc.

    Now, while I can see a tanuki being considered a dog (they're even called raccoon-dogs) and a fox is basically just a dog that thinks it's a cat, I would definitely not go so far as to call a bear, a raccoon, a weasel, or a seal a dog. While we haven't seen any of these as Zoans yet, and therefore could all still easily be Dog-Dog models, I highly doubt it, since they just barely skirt the line of what it is to be a dog even more so than the non-dog canids. Instead, I would think that there'd be a Bear-Bear series for Family Ursidae (grizzlies, polar bears, pandas, etc.), a Weasel-Weasel series for Family Mustelidae (weasels, badgers, otters, wolverines, maybe even extend it up to Superfamily Musteloidea to include skunks since they used to be considered weasels and would be standalone otherwise), a Seal-Seal series for Clade Pinnipedia (to include all Families of seals and walruses, cus dang, those are shockingly widespread taxonomically), and a Raccoon-Raccoon series (raccoons and red pandas, unless they're included in Weasel-Weasel for being Musteloidea).

    Now, it may seem like I'm playing it a little fast and loose here since I'm not sticking strictly to Families, but most of the places where I bent the rules were to avoid making unnecessary standalone models. Honestly, if you saw a seal Zoan and a sea-lion Zoan, would you expect them to be the same series or not? Pinniped doesn't even go quite as far up as Order, it just isn't considered a superfamily for some reason that is beyond me. Besides, as you'll see later, there is precedent for going even further up. This isn't nearly the craziest it gets.

    For now, though, let's move on to an easy one. The Cat-Cat series currently only has one canon member:

    Leopard Model.png
    • Leopard, Panthera pardus
    From this alone, we can't really tell much, just that other members of Genus Panthera (lions, tigers, jaguars, etc.) are almost definitely eligible. Still, given the name "Cat-Cat," it's highly unlikely that this series stops at the Genus, especially since the Dog-Dog series went up to Family. In the case of cats, that would mean going to Felidae, the entirety of which are colloquially referred to as cats.

    Though it isn't presented in canon, we can say pretty definitively that Oda considers non-Panthera Felidae to be eligible for Cat-Cat based on concept art of Marguerite:

    Black Cat Model.png
    • Black Cat, a coat pattern of Felis catus, or domestic cat
    While it's pretty weird that a coloration unrelated to breed is being specified for a Devil Fruit, but we're going to ignore that for now. What's important is that domestic cats are Family Felidae, but not Genus Panthera. Still, it's no surprise that domestic cats would be in the Cat-Cat series, since it's literally named after them.

    For further evidence, there is also a non-canon. albeit unnamed, Cat-Cat model in the anime:

    Cheetah Model.png
    • Cheetah, Acinonyx jubatus
    Being a member of Felidae, it's pretty safe that even though the cheetah model isn't canon, it would definitely be a Cat-Cat model as it is, in fact, a cat. Other members of Family Felidae include cougars, lynx, wildcats, ocelot, servals, etc. Much like the Dog-Dog series, I think it's pretty safe to say that suborder Feliformia won't spill over into the Cat-Cat series, so we won't see mongoose, hyenas, civets, etc. being attributed to the Cat-Cat series. Each of those is pretty different, so they'd probably be in their own individual series, single-model or otherwise.

    Now, it may be worth noting that the Cat-Cat series necessitates being able to include both Panthera and Felis, as members of Panthera just are really big cats and it wouldn't make any sense to have them be a separate series. With this in mind, since Cat-Cat goes up to Family, this may have something to do with why Dog-Dog does as well, since cats and dogs are seen as opposing animals. If Felis gets to have their Panthera and Acinonyx cousins, it only makes sense that Canis gets to enlist Vulpes and Nyctereutes.

    So based on the Dog-Dog and Cat-Cat series, the requirement is being part of the same Family. Case closed, right? Sadly, no. Our next series, the Bird-Bird series, complicates matters just a tad. There are currently four known Bird-Bird models, all of which named, two of which are canon:

    Falcon Model.png
    • Falcon, Genus Falco, likely either a lanner (Falco biarmicus) or peregrine (Falco pregrinus) since Pell is modeled after Horus. It is possible that the Falcon model is meant to be a generic member of Family Falcidae, but probably not since that would mean that it could be a caracara rather than an actual falcon, and I just don't see that being the case
    Phoenix Model.png
    • Phoenix, no known species since it's not a real animal and I can't tell what kind of bird it's based on, but it is definitely of Class Aves (birds)
    Eagle Model.png
    • Eagle, Genus Aquila, though exactly what species is difficult for me to conjecture. When compared to falcons, the two don't actually meet until you go all the way up to Class Aves
    Nue Model.png
    • Nue, a Mythical model of a shapeshifting tiger-baboon-tanuki-snake with no known taxonomic ranks at all. So...functionally useless for our purposes, at least until you look at its mythology. The nue has heavy association with birds, with the kanji (鵺) being made up of the kanji for night and bird, its call being reminiscent to that of the scaly thrush (Zoothera dauma), its original appearance being described as similar to the green pheasant (Phasianus versicolor), and its name being applied to the White's thrush (Zoothera aurea). Therefore, despite looking like a tiger chimera, it is possible that the nue is, in fact, some kind of bird, possibly due to shapeshifting, though this ability is not demonstrated in the One Piece x Kyoto exhibit it originates from. Regardless of which of these birds is used as the base, though, they only meet the previously mentioned birds at Class Aves, as you've probably guessed
    In short, anything that can be called a "bird" (all members of Class Aves) are eligible for the Bird-Bird series without any subdivision from there, as there is no Falcon-Falcon or Eagle-Eagle series to differentiate the various Genera within. This means that any bird, ranging from flightless (penguins and ostriches) to flightful (eagles and falcons), small (doves and canaries) to large (condors and albatross) are all fair game. So long as they have feathers, wings, beaks and claws, they should be eligible to be part of the Bird-Bird series.

    Or...at least it would be nice if it were that simple. See, Aves isn't technically a Class. For those of you unfamiliar, modern birds are, quite literally, dinosaurs, with Order Crocodilia being their closest living relatives. Therefore, Aves is, in some circles at least, considered a subclass of Class Reptilia. Now, the issue here isn't whether crocodiles are eligible for the Bird-Bird series, I can say pretty confidently that they're not. No, the bigger issue is this: where does the Archaeopteryx, the "first bird", fall?

    The Archaeopteryx was the transition from the flightless feathered dinosaurs to the flightful modern bird, but they were still undoubtedly Class Reptilia, clade Dinosauria (clades being a collection of branches within a taxonomic rank rather than a rank of their own). No matter how you slice it, Archaeopteryx would be an Ancient model regardless of what series it's in. The thing about that though is that we already have a series meant for dinosaurs: the Dragon-Dragon series. The Dragon-Dragon series currently has three known members:

    Allosaurus Model 2.png
    • Allosaurus, Genus...Allosaurus. Hm. Which particular species is unknown.
    Spinosaurus Model.png
    • Spinosaurus, Genus...Spin...osaurus...Thanks Oda. So obviously Allosaurus and Spinosaurus don't share Genera, nor are they from the same Family (Allosauridae and Spinosauridae respectively). They do, however, both come from Theropoda, a suborder of Order Saurischia. Being Saurischia, they are both from clade Dinosauria.
    Pteranodon Model.png
    • Pteranodon, another Genus-based Zoan of...Order Pterosauria. Okay, so not Order Saurischia with the other two, but at least it's from clade...Avemetatarsalia...not Dinosauria...Well...that clade also includes Dinosauria much later down the line so...they're at least related?
    So the Dragon-Dragon series doesn't refer specifically to "dinosaurs," since pterosaurs are distinctly not dinosaurs. However, the Japanese name for the Dragon-Dragon Fruit, "Ryuu-Ryuu no Mi", allows for a little bit of ambiguity. Because of the dinosaurs included in the series, one could reasonably conclude that the name comes from "kyouryuu," 恐竜, scary dragon (almost a perfect Japanese translation of dinosaur, or fearsome lizard), but in actuality, many ancient reptiles have "ryuu" in their name, including pterosaurs (yokuryuu, 翼竜, winged dragon).

    Going on a slight tangent, I feel that a more appropriate translation for Ryuu-Ryuu might be Saur-Saur, but given that Kaido's unnamed Fruit, which appears to be a long (Chinese dragon), may be in the Ryuu-Ryuu series, we'll allow it to stay Dragon-Dragon for now.

    Dragon Model.png

    Back to business, since the Archaeopteryx is of Order Saurischia and is thus a dinosaur, not a member of Class Aves, it only seems appropriate that it would be considered a part of the Dragon-Dragon series rather than the Bird-Bird series. Still, I don't think it would be inappropriate per se for it to be considered an Ancient Bird-Bird model, especially since its Japanese name, shishochou, 始祖鳥, refers to it as a bird (and we already know that's really all you need from the Nue), though something like the dodo (Raphus cucullatus) would be more appropriate for that role.

    The bigger question, though, is where the line is drawn. If the kanji for ryuu is all that matters, then modern lizards, which can be called tokage (蜥蜴, doesn't include dragon) or sekiryuu (石竜, does include dragon) could potentially be applicable. However, given the more fantastic nature of a series called "Dragon-Dragon," I'm inclined to believe that it's more likely that modern lizards would get their own series, possibly called the Toka-Toka no Mi (Lizard-Lizard Fruit), mostly because we already know that modern specimens of Class Reptilia are not automatically considered Dragon-Dragon models.

    The Snake-Snake series, comprised of...well, snakes, is completely made up of Serpentes, a suborder of Order Squamata (scaled reptiles like lizards, snakes and amphisbaenians). Thus far we have seen three models:

    Anaconda Model.png
    • Anaconda, Genus Eunectes of Family Boidae
    King Cobra Model.png
    • King Cobra, Ophiophagus hannah of Family Elapidae (interestingly, not actually a true cobra of Genus Naja, also Elapidae)
    Orochi Model.png
    • Yamata no Orochi, a Mythical snake with eight heads. Probably not meant to resemble any particular snake, but since it is a snake at all, we can assume it is of suborder Serpentes
    If it's Serpentes, it can definitely be considered a part of the Snake-Snake series, but we're still somewhat at a loss for the other squamates. After all, what is a lizard but a snake with legs? And amphisbaenians practically are snakes, just a bit more worm-like since their heads don't have a clear separation point from their bodies the way snakes do (and also some of them have tiny fore-legs, but we won't hold that against them). Still, we have no reason to think that lizards would be applicable to the Snake-Snake Fruit aside from being really close relatives, and as we've established with the previous series, the names themselves are what really matter, at least for these ones, so I think it's more likely we'll see a Lizard-Lizard series that includes the amphisbaenians (since they probably wouldn't get their own, their alternate name is worm-lizard, and their closest living relatives are Lacertidae, the true lizard Family).

    But what about other reptiles? We know snakes aren't part of the Dragon-Dragon series, but there isn't currently a reason why lizards and amphisbaenians can't be. Or is there? We still have three types of reptiles left to look at; turtles, crocodiles and tuatara. Let's see how they stack up. Starting with the easy one, we already know that turtles have their own series, the currently single-model Turtle-Turtle Fruit.

    Turtle Model.png

    Since it doesn't have a model name, it's possible that the Turtle-Turtle Fruit is meant to cover all reptiles under Order Testudines (sea turtles, tortoises and terrapins), but for reasons I'll cover a bit later, I personally believe that not only is it possible for the Turtle-Turtle Fruit to have other models, I also don't believe that there is such thing as a single-model series in the first place. For right now, though, all that matters is that turtles are distinct from lizards in Devil Fruit terms.

    Next, let's look at tuatara. Tuatara are visually pretty much indistinct from lizards, and in fact come from a sister Order to Squamata, Rhynchocephalia. Both Squamata and Rhynchocephalia are members of the superorder Lepidosauria. The reason why this is important is because there is only one extant species within Rhynchocephalia, the tuatara. Yes, an entire order is reserved for a single species. The problem there is that if the tuatara were to have a Zoan Fruit, it would be the "Tua-Tua Fruit," a single-model series that looks visually identical to a Lizard-Lizard Fruit, and would in all likelihood be functionally the same as well. Therefore, even if my idea that there aren't single-model series is incorrect, the tuatara is so lizard-like that it might as well be considered a lizard for these purposes, extending the hypothetical Lizard-Lizard series up from Order Squamata to superorder Lepidosaura or simply catching tuatara under the Dragon-Dragon umbrella.

    But if we're going that far up, what about Order Crocodilia (true crocodiles, alligators, caimans, etc.)? Aside from birds, people consider crocodiles the modern dinosaurs since they've barely evolved since the Jurassic period about 145 million years ago. Though they aren't lizards genetically, phenotypically they look like really big lizards, so why not bump Lizard-Lizard up one rank further from Lepidosaura to all of the modern members of Class Reptilia, or include all modern Reptilia in Dragon-Dragon?

    Well, because we're already making too many exceptions for that method. Snakes and turtles already have their own series, and frankly they're pretty low down the line if we're going to be going all the way up to Reptilia as a whole. It just doesn't seem fair to say "the Dragon-Dragon series is every reptile!...except snakes and turtles, cus reasons." That just doesn't sit right with me, so while it's perfectly reasonable to put tuatara in with lizards, reasonably crocodiles should be their own thing, leaving Dragon-Dragon to be all out-of-the-ordinary reptiles (Mythical and Ancient, though clearly with exceptions for ones that are obviously members of more specific series).

    So it's finally settled, right? All that matters is that an animal is genetically close enough to a group to be able to be called by a generic name. Case closed, we're done, everyone can go home.

    Except it still gets more complicated!

    Moving back into Class Mammalia, we examine the Ox-Ox series. There are currently two named members, and one unnamed member that is completely unquestionable as a member:

    Bison Model.png
    • Bison, specifically the European Bison bonasus rather than the American Bison bison. Either way, the bison is a part of Family Bovidae.
    Giraffe Model.png
    • Giraffe, Genus Giraffa, most likely Giraffa reticulata based on the fur pattern, of Family Giraffidae.
    Holstein Model.png
    • The unnamed Holstein cow, which I'm going to refer to as the Cow model, is clearly either meant to be representative of the entirety of Bos taurus or is meant specifically to be the Holstein model with other breeds of cow having their own models. I think the former is more likely though, since the Awakened Zoan seen with this Fruit is named Minotaurus and not Minoholstein. Either way, since the name "ox" (ushi, 牛, in Japanese) specifically refers to Genus Bos, I think it's safe to say that this is probably meant to be the base form of the Ox-Ox series. Family Bovidae is named after Genus Bos, making bovids "cow-like."
    My initial instinct was to consider the Ox-Ox series as encompassing all of Family Bovidae, though I shied away from this idea when I learned that this would encompass sheep, goats, gazelles, wildebeests, etc. From there, I figured that it would be more appropriate to make Ox-Ox refer to subfamily Bovinae (cows, bison, buffalo, etc.) while subfamily Caprinae would get the Ram-Ram series (goats, sheep, muskoxen, etc.) and the wastebasket taxon of antelope (several non-cow bovid subfamilies that include true antelope, gazelles, wildebeest, etc.) gets the Lope-Lope series.

    That idea, however, was completely trampled on by the giraffe.

    Like I said, giraffes are not bovids, they're giraffids, a Family which also includes okapi and several extinct shorter-necked giraffes potentially fit to be Ancient models. To be able to consider giraffes a part of the Ox-Ox series, we would need to go one rank higher up to Order Artiodactyla. So what's the big deal? We've gone as high up as Order before with all of the different kinds of reptiles, and even as high up as Class with both birds and ancient reptiles. Why can't Ox-Ox go as high as Order?

    Because that's a false equivalency. Bird-Bird being Class Aves is fine because all Aves are birds without question. All Serpentes are snakes. All Canidae are dogs. All Felidae are cats. Even the tuatara, as a sister taxon of lizards, can at least be called lizards by lay people because they look exactly the same.

    Yeah, giraffes basically look like stretched out cattle and their genders are bull and cow the same as cattle, but that doesn't mean we can call them oxen. Plus, if we include all of Order Artiodactyla, we can't just stop at giraffids. See, Artiodactyla refers to all even-toed ungulates (hooved animals that bear their weight on two toes, note the number of toes in the pictures above). If we consider giraffids to be oxen simply because of their hooves and the semantics of their gender, we would also have to include Family Camelidae (camels, llamas, alpacas, etc.), Cervidae (deer, moose, caribou, etc.), Suidae (pigs, boar, hogs, etc.), Hippopotamidae (hippos), and most egregiously, Cetacea (whales, dolphins, porpoises, etc.).

    Now, cetaceans probably wouldn't actually be included since they've long since evolved away from their hooves, so if they end up having their own Whale-Whale series (which I've already discussed as being a possibility in the past), they would likely be an exception the same way that snakes are excepted from the hypothetical Lizard-Lizard series. The rest though don't have the same excuse, as they are all, toe to tip, even-toed ungulates. And again, aside from bovines, none are even colloquially called oxen.

    Of course, it is possible that this was meant to be Oda's way of preventing a single-model series, as he likely didn't realize that okapi were also giraffids. In fact, this actually lends credence to my idea that there are no truly single-model series, as there could easily have been a Giraffe-Giraffe Fruit and no one would have complained. Instead, though, it's a part of Ox-Ox.

    Hippopotamids, similarly, only have two extant species, common hippos (Hippopotamus amphibius), and the much smaller pygmy hippo (Hexaprotodon liberiensis). If both are used, there could be a Hippo-Hippo series, but if there is only one Hippo model meant to include both, it wouldn't be too far-fetched to include them in the Ox-Ox series based on the precedent set by the Giraffe model.

    Still, unless all even-toed ungulates are a part of the Ox-Ox series, we'll be making a ton of exceptions either for what is or what isn't included. It would be that we're either looking exclusively at bovids with the exception of giraffids and maybe hippos, or that we're looking at even-toed ungulates with the exception of pigs, deer camels, goats, antelope, etc.

    I'm not saying that that won't be how it ends up, and in fact, since we have giraffes as part of the Ox-Ox series already, I would honestly prefer it that way, I just don't like that these are the options we're left with when it may have been more parsimonious to just have a Giraffe-Giraffe series in the first place.

    Before I forget, it may be worth noting that there is an unnamed, non-canon alpaca Devil Fruit.

    Alpaca Model.png

    Though we don't know it's name, we can conjecture that it is one of two things:
    1. If all even-toed ungulates are Ox-Ox, then it would be the Ox-Ox Fruit: Model Alpaca.
    2. If the various even-toed ungulates have their own series with some exceptions, then it would most likely be the Camel-Camel Fruit: Model Alpaca.
    Either way, because alpaca are members of other groups, it is highly unlikely that it would be a standalone Paca-Paca Fruit.

    But say that the Ox-Ox series is meant to be all of the even-toed ungulates. Where would that leave all of the odd-toed ungulates?

    While there are a number of unnamed odd-toed ungulate Zoans, there is only one named model, the single-model Horse-Horse Fruit.

    Horse Model.png

    We haven't seen the full horse form of this Fruit, so it's hard to gauge exactly what breed it is, but it is definitely Equus ferus, since that's the only extant species of horse there is as near as I can find. The fact that it's labeled a single-model series implies that it is meant to cover all of Equus ferus, though breeds of horses are quite varied in same way that dogs and cats are, so there's no reason we couldn't see a pony, thoroughbred, draft horse, or even a Mythological kelpie, pegasus or unicorn. This is one of the reasons why I don't believe in single-model series; there's too much untapped potential in the single-models.

    Continuing our analysis of the odd-toed ungulates, the other two that we've seen so far are both found among Impel Down's Jailer Beasts:

    Zebra Model.png
    • Zebra, Genus Equus, belonging to either subgenus Hippotigris or Dolichohippus. I'm willing to bet Hippotigris, since Dolichohippus is more donkey-like in appearance, but it honestly doesn't really matter since this one seems to refer to "zebras" as a whole.
    Rhino Model.png
    • Rhinoceros, one of any five species in Family Rhinocertidae. It's hard to say exactly what kind of rhino it is, but given that it has two horns, we can narrow it down to one of two as it seems to take inspiration from both the black rhino (the pointed shape to the area underneath the horn) and the white rhino (the second horn is significantly shorter than the first rather than being relatively even). This implies that the Rhino model is meant to be a generic rhino rather than having one model for each species, though there could be one for the two-horned and one-horned variants each.
    In the case of the zebra, I find it highly unlikely that it is a standalone model on the basis that it is, quite literally, a horse (equine) with stripes. If a giraffe, which by all rights should be a standalone Zoan is forced to be lumped in with the Ox-Ox series, there is absolutely no reason that the zebra should get its own single-model series to itself. Also, if zebras were standalone, then where would the third subgenus of equines, Asinus (donkeys), go? Neither zebras nor donkeys are different enough from horses in my opinion to warrant their own series, so until proven otherwise, the Horse-Horse Fruit is simply the base model of a series and as such didn't see a need to give it a subtitle.

    As for the Rhino-Rhino Fruit, it's hard to say how it would go about filling out a series. Like I said, there are two major types of rhinos, those with one or two horns. I'm not really sure that warrants counting them separately for the sake of a Devil Fruit, though. Even if it doesn't, however, the Rhino-Rhino Fruit can be the base form of a series with its other members being Ancient models drawing on extinct relatives such as: the woolly rhino, Coelodonta antiquitatis, which had thick fur and massive horns; the running rhino, Family Hyracodontidae, built for speed and sans horn; the aquatic rhino, Family Amynodontidae, adapted to living in water and very similar to a hippo, also missing a horn; or the crescent horns, Genus Menoceras, which had its horns side by side, among other possibilities.

    The final odd-toed ungulate presents a similar issue of diversity to the rhino, though even more stringent; the tapir (Family Tapiridae), while having five extant species, doesn't really have a ton of ways to differentiate its members aside from fur pattern and trunk length. While that could be enough, I just don't see it really making that much of a difference. The giant tapir (Tapirus augustus) may make a good Ancient variant, but I'm not really sure. I'm having trouble finding any other extinct tapirs that really stand out, but fortunately, I don't have to. Throughout a significant portion of Asia, including Japan, there is a mythological creature said to feed on dreams, known in Japan as the baku, with the trunk (and sometimes tusks) of an elephant, eyes of a rhino, tail of a cow, and paws of a tiger. Based on depictions of the creature in art, it is clear that the baku and Chinese equivalent mo were based on the Malayan tapir (Tapirus indicus). In other words, no matter what tapir is used as the base Tapir-Tapir model, there can always be a Mythical model based on the baku, likely given features inspired by the Malayan tapir and some measure of psychic abilities (likely expanding from eating dreams to erasing memories or emotions, as the baku could also eat hopes and desires).

    Of course, none of these are so far out of range of Equus that they couldn't be considered a part of the Horse-Horse series, at least no more so than a giraffe is separated from a cow. Still, since none of them necessitate a single-model series (though granted neither did the giraffe), I think it's fair game for them to have their own series.

    Speaking of single-model series, I think it's about time we go over exactly why I don't believe in them. For one, like I said earlier, there's too much room for possibilities that summing them up as one generic animal is doing them a tremendous disservice. The other reason, though, is that we already know that just because a Zoan model doesn't have a subtitle doesn't mean that it's a single-model series. In fact, there are two series that fit this criteria so far.

    First, the Elephant-Elephant series, with two models:

    Elephant Model.png
    • Elephant, of Family Elephantidae, though which species is unclear. Based on Funkfreed's large ears, the wrinkles on his trunk and the roundness of his head (not super clear in the above image, but certainly in other panels), I think it's safe to say that he's an African elephant, narrowing it down to either Loxodonta africana or cyclotis rather than the Asian elephant, Elephas maximus. I think it's africana, the African bush elephant, because his ears aren't totally round, but I don't know if that's really the be all end all for elephants.
    Mammoth Model.png
    • Mammoth, Genus Mammuthus, most likely Mammuthus primigenius on the basis of appearing to be a woolly mammoth, though I'm sure other mammoth species were heavily furred as well. Either way, mammoths are Ancient members of Family Elephantidae
    The second is the Human-Human series, also with two models:

    Human Model Heavy Point.png
    • Human, Homo sapiens.
    Buddha Model.png
    • Buddha or Daibutsu, arguably Homo sapiens since a buddha is a human that has achieved enlightenment. Either way, a Mythical variant.
    The thing about both of these is that in terms of extant species, there aren't really a ton of options, at least not in a real world sense. Like I said, elephants only have three species, and they really aren't that different. They're a bit different in size and have different tusk sizes, but the difference isn't nearly as drastic as the difference between a modern elephant and a mammoth. Humans, meanwhile, only have one extant species in our world. While they have a pretty decent variety in the world of One Piece (as I've covered in a previous theory, with the possibility that Fishfolk, Longlimbs, giants, etc. could all have their own models), there isn't currently any concrete evidence that they do have their own Human-Human series Fruit, so for now, humans are limited to our base model and Mythical variants.

    Now, both of those actually do still have a lot of potential going for them in Ancient models. If we expand the Elephant-Elephant series from Family Elephantidae to Order Proboscidea, we get a lot more options for extinct elephant-like animals such as mastodons (Genus Mammut), deinotheres (Family Deinotheridaes), anancids (Family Anancidae) and various others. Whether these are necessary considering that the Elephant-Elephant series already has two models is debatable, but at least the options are there.

    The Human-Human series also has a bunch of extinct possibilities, such as neanderthals (Homo neanderthalensis), Homo erectus, Homo habilis, Genus Paranthropus, and many others. I'm actually super interested in this topic in particular and plan to revisit at a later date, so if I can find the time to unpack all of that and manage to uncover enough information of interest, I will definitely explore the possibilities here to the best of my ability.

    The bigger question with the Human-Human series is whether or not it will include other members of Order Primates. My instinct is no, since humans are quite distinct from things like monkeys and gorillas, but there may be some argument that they would be included in the same way that giraffes and cows can both be in the Ox-Ox series. I don't personally buy it, though, and I honestly think it would be more like the Snake-Snake series, where a specific subset is excepted while all others, even if otherwise disparate, are summarized into one series. In this case, all non-human or proto-human primates would be in the Monkey-Monkey or Ape-Ape series, thus including monkeys, gorillas, orangutans, lemurs, marmosets, etc. All of those things are colloquially referred to as monkeys, so by the logic set up by earlier series, this should be perfectly acceptable. In fact, the proof that the Human-Human series wouldn't include monkeys is right there; it could easily have been a model of the Ape-Ape series, as we are called "hairless apes." No one would have complained. And yet, here we are.

    Quick side-note, while we're talking about primates, I'd like to discuss All-Hunt Grount's Devil Fruit. We're not given a lot of details to go off of, since it only manifests as Grount's arm rather than a full or hybrid transformation, but given the ape-like qualities that his arm has, I'm inclined to think that it's some kind of primate.

    Sasquatch Model.png

    The few details we do have, though, are that it has claws (extremely unusual in primates) and it's huge, dwarfing Grount's entire body when he used this Devil Fruit as a child.

    Sasquatch Size.png

    As near as I can tell, there are only two primates that have claws, tamarins and marmosets, both of which are extremely small, so they can't possibly be it. I'm sure that there are probably better explanations, but there's only one giant, clawed primate that I can think of: the sasquatch. I believe that Grount holds the Mythical Ape-Ape Fruit, Model: Sasquatch. This may even explain why he doesn't fully transform; the sasquatch is never meant to be seen, it only allows glimpses of it. This doesn't really relate to this theory as a whole, it's just a little addition I wanted to make while I had the opportunity.

    Even single model-series that seem like they would be perfectly representative of their whole group have room for further expansion, as is the case with our final named single-model Fruit: the Mole-Mole Fruit.

    Mole Model.png
    • Mole, definitely one of the true moles of Family Talpidae, but what Genus is pretty hard to pin down, since there are a lot of moles, most of which as near as I can tell look pretty similar.
    Like I said, most true moles from what I've seen are pretty similar looking, but there certainly are exceptions like the star-nosed mole (Condylura cristata), which the current Mole-Mole Fruit definitely does not represent. Even if we ignore that, true moles are spread out into multiple subfamilies of Talpidae, being Scalopinae, Talpinae, and Uropsilinae. Therefore, we could easily include the entirety of Family Talpidae, expanding out to shrew-moles and the semi-aquatic desmans (too many Genera to list), which are both burrowers like true moles, without worrying about taxonomic inaccuracy.

    Hypothetically we could also extend it all the way up to Order Eulipotyphla to include true shrews, solenodons, hedgehogs, etc., but those can't really be called moles. Again, it's no different from the giraffe situation, it just doesn't sit right with me. I think it's more likely that there'd be a Shrew-Shrew series that includes all of those, even though that wouldn't really be accurate either. Still, I have a bit of a hard time imagining how the non-talpid Eulpotyphla would be categorized otherwise, so that might just have to do.

    Just as the Mole-Mole series seemed like it was probably perfectly represented with its one model, there is another model that, although we haven't seen its base model, could easily have the same assumption made about it: the Bat-Bat series, currently represented by one non-canon Fruit.

    Vampire Model 2.png
    • Vampire, a Mythical variant, presumably based more heavily on the common vampire bat, Desmodus rotundus, than on humans-turned-monster since it's not a Human-Human Fruit. I say it's most likely the common vampire bat due to the pointed ear shape, rather than the short, broad ear shape of the hairy-legged vampire bat (Diphylla ecaudata) or long, rounded ear shape of the white-winged vampire bat (Diaemus youngi). I would have based it on the nose-shape, but Patrick Redfield is never depicted using the full-bat form, so it's hard to say if the nose he's presented with would be accurate.
    Whatever species the Vampire model is meant to represent, the fact that the series is referred to as Bat-Bat means that it most likely covers all of Order Chiroptera, which means that we could most likely see both suborders of bats: Megachiroptera and Microchiroptera, or megabats and microbats. Megabats (Family Pteropodidae) are typically the bigger ones that eat fruit and don't use echolocation while microbats are small, do use echolocation, and eat a variety of diets, thus having more varied dentition than megabats. Every iteration of vampire bat is a microbat, so it's certainly possible that the Bat-Bat series refers specifically to microbats, but I highly doubt it since there's no name that would fit megabats and exclude microbats. Regardless, since the Vampire model exists in the first place, we already know that the Bat-Bat Fruit is a series no matter how many variants it has.

    Going back to canon, let's look at another series with only one known model, but that definitely has more to it: Order Urodela, the salamanders, with the Sala-Sala series.

    Axolotl Model.png
    • Axolotl, Ambystoma mexicanum
    Among salamanders, there are a number of options for variants, which can be drawn from suborders Cryptobranchoidea (giant or primitive salamanders), Salamandroidea (advanced salamanders), and Sirenoidea (fully aquatic sirens). It's possible that the Sala-Sala series only refers to the advanced salamanders, as the axolotl is from Family Ambystomatidae of Salamandroidea, but as with megabats earlier, giant salamanders aren't so different from advanced salamanders that I'd be able to separate them out and tell them apart or have a name for them. Sirens, on the other hand, could have their own Siren-Siren series, as they are more eel-like in appearance than their brethren. Furthermore, the giant and advanced salamanders are grouped into clade Neocaudata to differentiate them from the sirens, making this possibility even stronger, but since there are advanced salamanders with similarly eel-like bodies to sirens, I'm going to go ahead and count all of Urodela for the Sala-Sala series. Also, I think it goes without saying that there would also be a Mythical variant for the fire-elemental salamander, which I'm going to go ahead and call salamandra to help differentiate it, since it would most likely be closest in appearance to the species fire salamander, Salamandra salamandra.

    Due to the name Sala-Sala, we can assume that this series does not extend up to include the other amphibian Orders, Anura (frogs and toads) or Apoda (caecilians), though there is a non-zero chance that it's meant to be the Class Amphibia series given what we've seen from other series. Still, I think that it's more like an amphibian series would have been called something like the Frog-Frog series given that frogs are much more well-known and bountiful amphibians than salamanders which are frequently mistaken for lizards.

    I anticipate a Frog-Frog series appearing later, likely covering terrestrial, aquatic, semi-aquatic and arboreal frogs and toads. There's a ridiculous amount of material to draw from for frogs, so I'm not worried about them having to rely on a singe-model series. The bigger problem are the caecilians, which look like scaleless snakes at their biggest and worms with eyes at their smallest. They do not in any way resemble frogs, so they definitely wouldn't make much sense to be a part of Frog-Frog, but they're not exactly close to salamanders either. They are somewhat close to sirens, with their long, snake-like bodies, but they quite simply are not sirens. You could shoehorn them into the Sala-Sala series, but honestly I think it'd be more appropriate to just give them their own Caeci-Caeci series. There are over 200 species of caecillians, so there's bound to be enough material in there somewhere.

    Next we move on to our final named series, and one that offers some unique challenges, the Bug-Bug series, of which two members have been named:

    Kabutomushi Model.png
    • Kabutomushi, Allomyrina dichotoma, also known as the Japanese rhinoceros beetle. In the official translation, this is known as the Rhinoceros Beetle model, so it's somewhat uncertain if other rhinoceros beetles are eligible, but I think that's more of an issue with the translation than anything else, as the hercules beetle (Dynastes hercules), atlas beetle (Chalcosoma atlas), and many others are perfectly distinct from the kabutomushi. Plus, kabutomushi specifically refers to A. dichotoma, and thus doesn't necessarily work as a catch-all for rhinoceros beetles or beetles in general.
    Wasp Model.png
    • Suzumebachi, Vespa mandarinia japonica, referred to as the Hornet model in English. Unlike the kabutomushi model, the English translation may actually be perfectly accurate, as "suzumebachi" can refer either to V.m. japonica or be the Japanese word for subfamily Vespinae (wasps, yellowjackets, and hornets), though it wouldn't be too much a stretch to extend it up to Family Vespidae given the similarities between members. That said, it could just as easily be specific to V.m. japonica, so this one could go either way.
    At this point, it probably doesn't surprise anyone to hear that kabutomushi and suzumebachi have no taxonomic ranks in common up to Class Insecta, indicating that all models of the Bug-Bug series will most likely be insects (although technically only models of Order Hemiptera can actually be called bugs). Of unnamed Devil Fruit, there are two that both have arguments to be made for and against being models of the Bug-Bug series:

    Caterpillar Model.png
    • Caterpillar, the larval state of Genus Lepidoptera (butterflies and moths). Its user, Epoida, is shown in a fully-human and hybrid state, so it's reasonable to conclude that this is a Zoan Fruit, but given the nature of caterpillars, this is somewhat up in the air. If it is a Zoan, this is definitely a Bug-Bug model, as all caterpillars are undeniable insects. The problems, though, stem from the fact that it's a larva: can the user of this Fruit pupate, and if so, into what? Will it allow the user to become a butterfly or a moth, and if so, what kind? If it becomes a specific butterfly or moth rather than a generic one representing either, do all Lepidopteran models need to undergo metamorphosis and start as caterpillars? Will it be random what it becomes? What triggers the transformation: desire, intentional gorging, random chance? This could very well be either a Paramecia in which one starts out with caterpillar characteristics and can't go full caterpillar, then pupates to gain Lepidopteran characteristics without going full butterfly or moth, or an unknown classification like Baron Tamago's Egg-Egg Fruit which can still easily be any known or an unnamed type of Devil Fruit. I've mentioned in the past that the Egg-Egg Fruit might be a Special Paramecia (or possibly even a Special Zoan, though I think that's what Mythical models are), maybe Epoida's Fruit is too. There's a ton of variables here and it could easily go in any direction. For now, though, we'll just take what we've been given at face value and call it the Bug-Bug Fruit, Model: Caterpillar.
    Spider Model 2.png
    • Spider, most likely Araneus ventricosus given that the wielder's name is Onigumo, the Japanese name for this particular species. Though it's tough to say from the evidence provided whether this in fact the case, I am fairly confident that there is a Spider-Spider series which would include all of Order Araneae. I would even personally be willing to include other members of Class Arachnida, such as the harvestmen of Order Opiliones (also known as daddy longlegs) and the solifuges of Order Solifugae. I'm not sure about scorpions (Scorpiones), ticks (Parasitiformes) and mites (subclass Acari), as I think those could easily have their own Scorpi-Scorpi and Mite-Mite series (probably both ticks and mites) respectively, but lumping all arachnids with spiders probably wouldn't be too egregious.
    While it's most likely that the caterpillar belongs to Bug-Bug and spider belongs to Spider-Spider, there is another, albeit unlikely option: Bug-Bug refers to all members of Phylum Arthropoda. This would allow for the inclusion of subphylum Myriapoda (centipedes and millipedes, which are often called bugs), Class Entognatha (hexopods which were once considered insects but no longer are), subphylum Trilobitomorpha (extinct, possibly Ancient models of the Bug-Bug series) and subphylum Crustacea (crabs, lobsters, shrimp, etc.). Now, I would not by any means consider crustaceans to be bugs, but honestly the rest of those are, at least colloquially, pretty much up for grabs in that regard. That said, we've already established that Oda is perfectly willing to make exceptions, so Bug-Bug could very well be used to encompass subphylum Hexapoda, Myriapoda and Trilobitomorpha but leave out Crustacea and Chelicerata (Class Euchelicerata, arachnids and horseshoe crabs, and Class Pycnogonida, sea spiders). Given that horseshoe crabs are closer to spiders than they are to crustaceans, it's hard to say how they'd be classified given that they're called crabs, so it's possible that crustaceans and cheliceratans would be lumped into a collective Spider-Spider, Crab-Crab, or other, similarly named series, though I'm willing to bet they'd be separate with horseshoe crabs misplaced in the Crab-Crab series due more to human error on Oda's part than anything else. Either way, we do already know that crustaceans are on Oda's radar, given that he planned for Inazuma to be a crab Zoan.

    Crab Model.png

    And now, my friends, at long last we have reached our final, unnamed Zoan Fruit, and believe me, this one's a doozy: the koala.

    Koala Model.png

    The only extant species of koala, Phascolarctos cinereus, carries a number of possibilities and implications for future possible Devil Fruit. If single-model Fruit are allowed this one's super easy, since there's no way for there to be any other variant models. There could be a Mythical variant with the dropbear, but the only real difference between a dropbear and a koala is their teeth (dropbears being carnivorous koalas). As I think has been well established by this point, Mythical Zoans are those that have some kind of special ability more akin to a Paramecia, and the dropbear just doesn't really seem to cut it there in my opinion. Granted, I don't know if having multiple heads is enough to call the Orochi model "Paramecia-like," but we could still see more abilities from that. Either way, I'm not relying on the dropbear just yet, nor am I compromising and calling the koala a single-model series.

    So how do we get the koala to be a part of another series?

    The easiest solution would be to have a series dedicated to infraclass Marsupiala, possibly called the Marsup-Marsup or Joey-Joey series (I like the latter myself, but of course I of all people would), but I don't really think that's a viable option. See, while all marsupials do share the unique characteristic of having a pouch that they nurse their fetal young in rather than laying eggs or growing them internally, that's not really enough to go on. The birds of Aves are all just that; birds. They all have wings, beaks, claws and feathers, and have generally the same basic appearance with unique differences. Insects all have six legs, an exoskeleton, three-part bodies, antennae, and compound eyes. When you look at a bird, you know you're looking at a bird, and when you look at an insect, you know you're looking at an insect. Marsupials, on the other hand, don't have a list of unifying characteristics, they have one characteristic in common between them, and that one characteristic opens up a whole slew of trouble. Remember the alternatives I listed to pouch-rearing? Basically, if we have a series dedicated to marsupials, then it would only make sense to have one dedicated to monotremes (all two mammals that lay eggs) and one dedicated to placentals, which covers literally everything else. Every dog, cat, ox, horse, primate, elephant, bat and mole would be covered in one group if we were to lump all placentals together. Sure, with the monotremes that might be a necessity for avoiding a single-model series (though still not ideal since platypi and echidna are not at all similar otherwise), but that's assuredly not the case with marsupials.

    We could narrow it down to Order Diprotodontia, but this still lumps koalas into the same category as kangaroos and possums, which are still just too different to make any logical sense. A giraffe may look like a stretched out cow, but a koala and a kangaroo don't even begin to look similar.

    As far as I can tell, the best option for the koala is to go down as far as suborder Vombatiformes, which pairs the koala with its closest living relative, the wombat. Fortunately for our purposes, a wombat basically looks like a small-eared koala that decided climbing trees was too much work, so making the Koala Fruit a model of the Wombat-Wombat series works perfectly for us.

    The rest of Diprotodontia is just as easily sorted, with Macropodiformes (kangaroos, wallabies, quokkas, etc.) being suitable for a Roo-Roo series, and Phalangeriformes (possums, gliders, cuscus, etc.) can have a Possum-Possum series, or a different name if Oda wants to give that name to a series dedicated to the American opossum (a similar looking, but pretty much unrelated marsupial).

    There are a few other marsupial Orders that don't really have much going for them individually, like Microbiotheria (only one species, monito del monte, which looks like a little tree hamster), Dasyuromorphia (Tasmanian devils, quolls, numbats, etc.), Notoryctemorphia (marsupial moles), and Peramelamorphia (bandicoots and bilbies), but each of these could probably be finagled to work one way or another. The latter three, all being terrestrial quadrupeds, are probably close enough that they could fit under one banner without too much issue, though I'm sure they have enough to go on that they could work in a pinch. The monito del monte, though, might be a bit more of an issue, but if we're lumping unrelated things together anyway, it could potentially be put in the Possum-Possum series on the basis that that's what it looks the most like.

    And with that, we've covered everything that we have seen thus far. With all of the information we've gathered, what can we conclude? In my opinion, it seems that there are three general guidelines:
    1. Morphology. First and foremost, it needs to look the part. So long as it has a number of set characteristics in common, it may work
    2. Genealogy. Even if it looks like it, that doesn't automatically mean it's applicable. It needs to be relatively closely related, but how close can vary
    3. Nomenclature. If it can at least technically be called a member of a group, it fits
    If morphology was the only important factor, we'd end up with a coconut Zoan because they have fur and produce milk, just like a mammal. Of course, it is still technically possible that Oda would take a morphological approach in order to better organize some of the stragglers. For example, if he made the Elephant-Elephant series refer to all of Order Pachydermata, a defunct order which was based around animals with tough skin, then it would include rhinos, hippos and tapirs, all groups that were discussed as being tricky to place earlier. Still, thus far, no Zoan series has shown any evidence of including members that aren't at least somewhat related. The furthest separated are the Dragon-Dragon series models, which are all at least colloquially referred to as dinosaurs and are genetically all reptiles.

    So now that we've covered everything that is known, I would like to take some time to talk about a few groups we haven't seen yet, just cus I think it'll be fun.

    One I'd particularly like to see is a Rat-Rat or Mouse-Mouse series including all of Order Rodentia, which, along with the obvious, would get us squirrels, chipmunks, capybara, hamsters, porcupines, beavers, and several others. Though they were once believed to be rodents, Order Lagomorpha would not be included and would likely get their own series. I imagine it would be either Rabbit-Rabbit, Bunny-Bunny or Hare-Hare, and would obviously include rabbits and hares, but also probably pikas and would certainly have a Mythical variant for the jackalope and its winged cousin the wolpertinger. If we're talking morphology, either group could potentially house hyraxes (Order Hyracoidea), but they're not particularly closely related to either, and in fact are closer to elephants and manatees. It would be pretty funny to have a Hyrax model of the Elephant-Elephant series, but it really doesn't seem appropriate based on appearance.

    For one that reaches all the way up to the Phylum, we could have a series for Phylum Annelida, or segmented worms, called the Worm-Worm series. This would include earthworms, leeches, and ragworms, among other worms. We probably don't have to worry too much about that name taking Zoans away from Phylum Nemotoda, the roundworms, since most of those are microscopic, though there are some that get as big as a meter in length. Worst case Worm-Worm could refer to all things called worms, extending to Phylum Platyhelminthes, the flatworms, but honestly this is starting to get kind of silly. If this came to be, though, I think it would prove pretty definitively that morphology and nomenclature are the most important factors rather than genealogy.

    Phylum Mollusca certainly wouldn't get a series to itself, but its constituents, Classes Gastropoda (snails and slugs), Bivalvia (clams, oysters, etc.) and Cephalopoda (squid, octopuses, etc.), along with some other smaller Classes could easily get their own series; likely Slug-Slug, Clam-Clam and Squid-Squid, with the other Classes squeezed into whichever ones they most closely resemble.

    Pangolins, one of my favorite animals, are pretty hard to classify. They could have their own series for Order Pholidota, with one model representing all of the larger, terrestrial pangolins and one representing the smaller, arboreal pangolins, but I would personally like it if Oda bent the rules a bit to have them counted together with the defunct Order Edentata. This would allow them to be grouped with the single-species Order Tubulidentata (aardvarks) and Order Xenartha (anteaters, armadillos, and sloths). What's interesting about xenarthans is that when taken together, they don't seem to resemble each other at all, but when you bring in pangolins and aardvarks, it makes a really interesting Venn diagram where their traits start to overlap: pangolins and armadillos both have armor, pangolins and sloths have similar claws, aardvarks and armadillos have similar heads, pangolins and anteaters have the same tongues, etc. When looking at any two, they don't fit as a group, but taken all together, it surprisingly starts to work. Shame they aren't actually related and don't have a good catch-all name. I guess I'd like it to be Arma-Arma for armadillos and pangolins, Vark-Vark for aardvarks and anteaters, and Sloth-Sloth for sloths, though I'm sure all of this overlap is completely needless as these are all pretty relatively varied groups save for the aardvark.

    Obviously, the rule about no single-model series is something I made up. It's my interpretation, and it may very well not be reality, since there are plenty of standalone species in the world, such as the koala, platypus, and aardvark. In the end, if you have any Zoan Fruit that you want to use for original characters or roleplays or what have you, it's your decision how you classify them, but I hope that I've been able to give you a decent idea on how to go about doing that.

    As for me, now that I've analyzed the rules that separate the different Zoan series, a new question has arisen: what are the rules that separate the models within? Stay tuned.

    Thank you all for reading,
    Tokiro Oumaga

    [Note: if you have any thoughts on that, I urge you to please wait until part 2 is uploaded. Please keep all comments on this theory limited to the content covered within.]

    Thanks to users like @Rohan , @Okamakama , and @Name Is C for encouraging me to get back into making theories and having faith that I'd come back someday. I hope that this one and its follow-up live up to your expectations, but if they don't, don't worry, I have more cooking as we speak. The only problem is that between work and grad school, I was only able to make progress on this one about a paragraph or two at a time per day. I'm going to try to get part 2 and all of my other series out as quickly as possible, just please be patient with me.

Recent Reviews

  1. BucketLover
    Really long, though i can tell a lot of thought had been put into it. I personally believe it doesn't actually have a logic since df were around for a long time most of the names could be traditional names from people from before scientists started studying them and officially naming them. Anyway, good job on this one! :D
  2. Hades
    the hell with this theory...lol...I think I have read some taxonomy subject instead of theory...I lost somewhere in the middle...but I can tell you it is really interesting.....
  3. Xatch
    5* for the return of an old theorist... plus I love world building theories and not mainstream hype... glad your around
    1. Tokiro Oumaga
      Author's Response
      This is the most validating thing I've ever heard. Thank you so much my friend.
  4. Donal D. Trump
    Donal D. Trump
    Honestly, I hope p.2 will rock my socks off and will be filled with more relevant stuff. After reading the theory I didn't learn anything on how devil fruit function and this is purely an academic attempt to determine if Oda is paying attention in his naming scheme. Otherwise for the hard work I got to give some respect, especially if the theory is so well written.
    1. Tokiro Oumaga
      Author's Response
      Haha, that's more or less all that I really wanted it to be though. I don't think part 2 will be anything ground breaking, but I hope you find it interesting.
  5. Nessos
    I think you could keep it much shorter. By explaining
    Horse fruit => all odd toed ungulate
    Bull fruit => all even toed ungulate

    With Cat and Dogs we can say for sure: Taxomie for mammals are either "order" or "suborder".

    Same for Reptile, because we have Turtle("order"), Birds("order") Snake("suborder") and Dragon aka Lizard("suborder")

    For insects I would say the taxomie is "classes".
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