Scrawny? Little? There are certain things that Firo can't just ignore.

The flames do take him aback; he blinks a few times to make sure he's not just seeing things. Even being in this place for a while, he still doesn't totally accept things like magic. But he decides to ignore it for now--letting himself be distracted could be dangerous.

He steps off to the side to stay out of the way as Rin attacks some of the zombies. "You want a fight, kid, you can have one. If the zombies don't take care of you first."

Firo, for his part, has no plans to run. He instead sets his knife on the first zombie in arm's range, keeping an eye on Rin all the while.