Redon's spoiler said that Rebecca defeats some fighters without hurting them. She can use Kenbunshoku Haki. No, I didn't actually think that Rebecca having conquerors haki/haoshoku haki. From what's being stated in Redon's spoiler, what I meant was, what else could defeats some fighters without hurting them? and the fact that kenbunshoku haki is only used to avoiding all the enemy attacks. But, @Shockingly has a good explanation about it. Well noticed, it seems that you've been paying a lot of attention for every plot in this story arc. And also details of their fighting style. I didn't pay that much attention because I'm less interested in Riku/Rebecca background.