WOW, was that Maekawa, the other kid he had to fight? That would be poetic, if that's the case. And since Maru's still reacting to the knife, I don't think he's being stabbed there, maybe marked, like they marked Maekawa's hand?
Also, damn. I feel for Paisen, but I'm mad, because now the worst person out of all of them will be his favorite - because of that "love" shit.