Oh, we usually murder our way to the top and claim victory whilst astride a pile of mangled bodies. But we're heroes so it's okay when we do that.
— Fighter, 8-Bit Theater
There is no right or wrong apart from what you decide. Who you choose to defend deserves to be defended simply because you chose them. You are the Fire Lord. What you choose, by definition, is right.
You think I'm evil? I AM JUSTICE!
— Light Yagami, Death Note
I'll prove I'm a good guy even if I have to destroy this entire city and beat you to a pulp!
I see my reflection in the window
It looks different, so different than what you see
Projecting judgement on the world
This house is clean babe
This house is clean
"When the President does it, that means that it is not illegal."
Kuyou is the kind of guy who believes without a doubt that everything he does is for the sake of justice. Anyone who goes against him is going against justice, and is an evildoer.
— Gin, Rosario + Vampire
Uriah: Then I hope you have foreseen the consequences of a world bereft of religion.
The Emperor: I have. It is my dream. An Imperium of Man that exists without recourse to gods and the supernatural. A united galaxy with Terra at its heart. [...] These warriors shall be my generals and they will lead my great crusade to the furthest corners of the galaxy.
Uriah: Didn't you just tell me of the bloody slaughters perpetrated by crusaders? Doesn't that make you no better than the holy men you were telling me about?
The Emperor: The difference is I know I am right.