Need Spell Name

[HMS Invincible]

There's a spell that enhances your stats by taking stats from a demon that you bind. There's varying options where the demon/devil can hunt you down. Anyone know what spell it is?

[Flickerdart]

There's a spell that enhances your stats by taking stats from a demon that you bind. There's varying options where the demon/devil can hunt you down. Anyone know what spell it is?
Extract Gift, Fiendish Codex I.

[Jeff the Green]

Or possibly the investiture spells from FCII.