Okay, here's the concept:
The character, a criminal mastermind with psionic abilities has developed an ingenious way to avoid being discovered and captured: his true personality retreats deep into his subconscious mind and leaves a personality construct in its place in his conscious mind. This "shell personality" is so exquisitely detailed, including its own set of memories, that it will pass muster under most forms of scrutiny, even telepathic scanning short of a deep probe into the subconscious. The shell is, of course, unaware of the fact that it is a shell; which is a major part of what makes it believable. His true self, meanwhile, is still aware of what goes on while the shell personality is up and can easily reemerge once the pretense is no longer necessary. This, coupled with the fact that never allows even his own minions to see his true face, has kept the authorities from discovering his identity and taking him down.
Would it be best modeled as Mental Group Shape Shift or Multiform? And what Modifiers would logically apply?
Thanks.