I may had some influence on Shion but it wasn't like Shion was so pure inside.
Yeah, Shion was never that pure to begin with, just like Lawl said:
It wasn't just the Rikiga scene though. Shion already showed violent tendencies when he was twelve ("Destroy it all" and such).
But Nezumi is too messed up to understand it. Like Shion told him, Nezumi can just see black and white and nothing in between. Shion is either good/pure, or he is a monster and evil. He should be a monster and evil, since he’s from No. 6 and he starts to think like that again when they are in the pit, because I guess his nerves are super raw. Even though he’s trying to act tough, I’m pretty sure this is a horrible mental situation for him (for Shion as well, but especially for Nezumi who’s already deeply traumatized…) But Shion is not just pure and not just evil. He is both, because he’s a normal human. He has his flaws… but Nezumi tends to put him on a pedestal… but Shion is the same, somehow he’s also doing this, even though I think Nezumi is worse. He’s not fair, absolutely not fair.
I think, Nezumi also has to learn that there’s not just black and white, but also grey. Shion taught him so… it’s not just Shion who’s getting influenced by Nezumi, maybe it’s Nezumi who’s even more influenced by him. Shion is just Shion, and I’m pretty sure Shion would also have killed if it were for Safu or his mother when he’s in such a situation. I think he’ll defend everyone he loves like that, if necessary.
Shion is not a saint. And he never said that he is one. He’s gentle and seems to be a nice boy, but he can be cruel as well… the bee inside of him suppressed a lot of his true character and his emotions as well, so it was not just Nezumi’s doing, even though he showed him the real world and helped to change his point of view in regard of No. 6 a bit…