The build I posted could be done without flaws and without the homebrewed PrC. At it's core it's just a buffed ur-priest that can possess people via Magic Jar. He is in a party with an Incantatrix, so I didn't "waste" feats on DMM: Persistent, when the Incantatrix can do it "for free". Originally it didn't include Binder or Anima Mage, either. It was based on a Hexblade/Human Paragon base.