[And Katara thinks of a scared little girl with burns on her back, fingers a half-remembered pain on her arm absently.]

I guess he's got his reasons to keep himself a secret.

[She pauses for a moment.] Sokka made a signal for him once. It was a giant bat projected into the sky. He said that he spoke with him. But... that was before he went home. I know that he uses weapons when he fights, but that's about it.