[Envy slams his fist into the nearest available thick branch. He's not mad at you, Tulio, he's just extremely frustrated with the situation.] I don't know why I'm going to be fighting him! He won't tell me, and there's a lot of things it could be.

[He lets out a short, not very humored laugh.] I'm not the most popular person among the humans who know I exist in my world.

...it's a guy named Roy Mustang.