Why is Roy mustang like so much?

If ya ask me, he's a total badasswhen he's using alchemy. There are some parts if his character I l’amour (like how badass he can be) and others that I don't.

He's very serious person, but he has made me laugh on many occasions. He's been through so much, and yet he stays strong and cheerful. I also l’amour watching him with Riza.