"Considering that my world doesn't have monsters, I'd say that isn't normal in the slightest." This is Strange teasing. He's got no qualms about the mercenary band killing things nature of Beau's work: he's a soldier, he's got to be fine with that sort of thing. He's just teasing her a little because he can and because he's got a feeling she'll find the monster-less state of his world so friggen weird.

"What sort of things did you kill?"