"He has to be banished. Off the ship. Other people are working on it. In the meantime, you need to try to learn to keep him out if there's anyone on the skyship that can teach you," Aang says, deftly hopping over a low-hanging branch in the trail.

"I don't know who the Shadow King is either, but the Nightmare King is--he's not a person. He's not alive. He's something like a spirit--but not one like me or any spirit I've ever met."