Nen. Aura? [It's a long shot, even if Hibiki were from the same world. Nen's not widespread knowledge even back there.] Never mind--it's something that can boost your strength and defenses if you know how to use it. I haven't been able to use it ever since I got here, though.

[Actually, about that. Killua looks over at Hibiki again.]

That demon contract you had before. You said it works differently now?