I don’t like this typical use of hatred as an excuse for the racism either, but some comments seem to be missing the point where at this point it’s blind hatred being churned in a vicious cycle. Both sides have immense loss which fuel their hatred.
Sure, it’s the oni that are being primarily persecuted and killed despite their innocence, but it’s also a fact that their presence and berserk nature is a threat to the majority. The situation could definitely be handled better from an organizational perspective, but this is such a long running feud there is little chance for easy change at this point. Even the MC, an oni raised by a mamtaro, doesn’t seek to reach peace but rather pursues revenge against a mamtaro. I’m not saying he isn’t justified to seek revenge, but rather it’s not easy to toss aside those feelings of revenge for a more peaceful approach.
Now to get back to this particular chapter: this villain is a piece of shit through and through, so much so that it disgusts even the other mamtaro involved, and the author didn’t make his backstory appealing at all. I dislike the disconnect in personality that was shown in the backstory, because previously he seemed very half-hearted before joining the team but now he’s full on psychotic and sadistic. There’s no real explanation given for why that is, even with the trauma of losing his friend and the family he became close with. The only major explanation would be that he’s always been like that, and his friend’s dying words became a trigger for a dangerous and disgusting obsession. Or perhaps it’s his own power of pseudo-necromancy that corrupts him. But again, there’s no tangible given explanation so it’s just lame.