I am Legion
Daimonion 3, Obfuscate 2
One of the Baali's most devious methods of avoiding detection, this subtle magic allows the Balli to forge a temporary pact with a "speaking demon" or other malevolent spirit (Storyteller's discretion as to what sort of being is appropriate). Once the pact is sealed, the Baali's partner in mischief temporarily leaps into the vampire's body, assuming a state of limited control over its voice and movements.
While the Baali is "possessed," the interloper who answers is essentially in charge, allowing for a certain amount of leeway when it comes to answering uncomfortable questions. After all, the demon can answer questions (truthfully) that might otherwise prove difficult for the Baali to respond to under magical, Auspex-based, or other scrutiny. For example, the demon within may cheerfully answer "no" to such tired questions as "Are you a Baali?" or "Do you engage in the worship of demons?" In a pinch, the demon may attempt to pose as Caitiff or even mortal; "I am clanless" and "I am not a vampire" are both perfectly reasonable true statements for a non-vampiric creature to make, after all.
System: The player must succeed in a Manipulation + Leadership roll (difficulty 6) to ensnare a suitable demon or spirit. The number of successes dictates the summoned creature's intelligence and willingness to help, which in turn indicates the extent to which it is capable of concocting useful reactions to pertinent questions and/or situations. A failure indicates just that - failure to ensnare the being - while a botch can result in a true catastrophe (a creature who does not wish to leave the caster's body, or who betrays her, at the Storyteller's discretion).
Baali hedging their bets with this sort of deal can make "concessions" to the inhabiting creature to win more cooperation. It is up to the Storyteller to determine what sort of goodies the possessing demon might want, what it could give in return, and whether or not it will keep its bargains.
