Quote Originally Posted by AssertnFailure
Kabuto would seem to be the most likely candidate...especially since he's always seemed so flaky in the past.

Wouldn't that be interesting....
Kabuto being a spy for akatsuki as a spy for orochimaru as a medic nin for Konoha.
So what they just passed him around as a child or something, orphan to medical squad, medical squad to akatsuki, akatsuki to Orochimaru and then back to the leaf as a spy for Orochimaru. I mean he is supposed to be only 22 now they must have passed him around more than addicts pass needles although that would explain why he is so messed up.