[Thankfully, not very far at all once Roxas locates a dead end branching off from the main hallway with a bench at the end. It's quiet enough since they're farther away from the party, so he sinks down onto the bench, already partially lost in thought.]

Where to begin... [A sigh. There's way too much to explain, and he doesn't exactly want to mark himself as a bad guy.] I guess you could say I've been in this situation before, except I had to travel to different worlds, fighting monsters. [He gives a dismissive gesture, not too keen on going into detail.] All I can say is that I don't want you to be tricked like I was. If my guess is correct, neither side is right here if the Shards are like Hearts.

[Which doesn't explain why he's been brought into this mess, but whatever. Roxas taps his chest where his should be.]

Aang, are you familiar with the Heartless or Hearts? Not every world is familiar with them, but...