Thrallherd, /tg/. It's a paragon path in D&D 4e open to Psions that gives you constant an total control of a minion that can be anything from a generic beast to a sentient humanoid your party has encountered before.

Psionic Power, where it's found, offers up that it's a good idea to play it as a megalomaniacal mastermind, goading others over your thrall, and implying that perhaps they are all your thralls and just don't know it. To me, though, that sounds like an excellent way to find two daggers, a shortsword, and a battleaxe lodged in the red paste that was once your body.

So, good ways to roleplay a psion that has constant and unwavering mental dominion over a single creature?