As you read the title it perfectly fits , Eren will be the final bad guy isayama is going to make . With how his character progressed in 106 it seems to me Isayama has already planned no new villain but none other than our hero whom we cheered Eren Yeager . Let me tell you why his action were villainous than heroic in the eye of survey corps . 1. Considering how his personality has changed after going through Eren kruger , he made a choice that he needs to unite all the titan before he dies . it all seems like Eren decided he cannot take burden of others help considering he has outpaced and grown stronger . 2. His method of planning involves more of innocent civilians dying with no fault of their this ironicly Marley is feeling same distort as with Eldian of paradis did in chapter 1 . 3. Introduction of Gabi - Pure heart Marleyan with Eldian blood , oddly Isayama introduced a hot headed female version of eren kind of ironically reminds how eren was when titan killed his family . 4. War is the only solution for the titan shifter not getting passed to younger generation this is only thing I can see Eren can possible think with war looming if he wants to collect all titans and die in the process and with that titan might actually get erased off from this planet . This could be the only solution I can think off for all the titan problem everyone has .