Why Is Sesshoumaru a full youkai? Sesshoumaru is Inuyasha's brother, but he is a full youkai, while Inuyasha is half human, half youkai. Why this happened? Don't they have the same mother and father? Wasn't he supposed to be half youkai too?
They don't share the same mother. Sesshoumaru's mother is a dog-type Dai-Youkai, while Inuyasha's mother was a human.