[Xiao will... maybe See in the future, even if D does not wish that on Xiao.]

Yes. Physical extensions of what would be our souls. A channel for magical prowess, mental Communion, and also Discord. If yours is left outside of your body for too long, your body will wither and disappear.

[He does not warn Xiao not to let others get a hold of such a thing; he can tell Xiao probably already understands that very well. It's important enough to not flash it around willy-nilly.]