Yeah I was thinking that too, her mother was probably human then. Maybe Kaido is bitter towards humans because her potentially human mother died too, maybe in childbirth? Or she just died and he is hateful about "humans being weak" due to that too?
I even suspect Kaido isn't "full Oni" and thus thats why he seems so different and more human than Oars and Jr, also much smaller than them too.
@Ravagerblade @Twin Milf