i always think some organization tried to stop MC to change past because it can result killing a person indirectly in future . . . or some heavy consequence changing the past . . . i don't expect Hannibal type tutoring . . .
inb4 another twist is that those he killed were just people he got sentenced to death . The line >>i win if I kill as many as possible reminds me of a somewhat familiar meme/shitposting line.
now I think it is entierly possible that the one who killed Todai's parents was Todai himself because that was the only way to either stop himself or Hidaka or sum bullshit like that.