Are we talking about a physical threat or a spiritual one? Physical threats are easy, I like the above suggestion for a silver tongue. A whip-like silver tongue with sharpened edges would give them reach, a damaging weapon, and could potentially be a good surprise attack.

If we are talking about a spiritual threat then I might recommend making them linked to Eater-of-Souls and the greed inherent in a pyramid scheme. A tempting sounding offer for a chance at riches draws in one person who then realizes they have been had and the only opportunity to save themselves is by preying on...