I'd supposed he comes from a time where he either has no memory of what you've done for him or has it yet to happen.

[ Really, Rin. Your reactions just make his job so much easier. Or.. rather his hobby. Now he's gone to play with one of those perpetual motion thingamabobs sitting on his desk while going on. ]

Telling him what happens would, however, be a rather poor course of action. You've heard of a time paradox, haven't you dear boy?