it was really hard to choose, but i'd rather save my favorite, even though we'd never be together, at least they'd be safe

I couldn't kill anyone.

Agreed. I have used Light for this example because he is my least favorite (which is probably clear), but despite how much I despise him and am against what he is trying to do, completely, I could never kill him. It would contradict all that I stand for, and I would become a hypocrite. I would become equal with Light.

Marry then divorce ;3

For one I don't want to kill anyone (especially not my favorite) plus I wouldn't be opposed to my favorite taking over the world.

I couldn't hurt or kill anyone,so definitely this one.

I cant think of a least favorite right now so

My least favorite was a guy so I just picked my least favorite female character, Kyou from Clannad. Her taking over the world doesn't sound that bad.

I couldn't kill anyone :P Especially my favourite character for that matter...
And I can't actually think of a least favourite character tbh hhaha

I'd get married, allthough hummm, my least fav anime character is a girl soooo....akward, but yeah i'd marry her.....