Lean

Yandere/possessive Sabo loves Luffy and wants to protect him no matter what. Especially from anyone who wants to take his innocence or away from him.

Luffy lives in an apartment with Sabo, Ace is at college out of state. Sabo is obsessive about protecting him from Ace; even though Ace has done nothing wrong.

Potential gore later on, I'm not sure though. I doubt Sabo would hurt him, just because he's so obsessed with sheltering him and keeping him 'innocent'.