[That works, too. Besides, aren't vampires basically parasites, anyway? Like giant goth tick monsters.]

Not at all. In fact, I cannot draw mana from an unwilling partner, even if I wanted to. They must offer theirs to the spirits by channeling, or they must agree to let me tether directly off their power.

And as a special way of thanking them, I will lend the power of my artes back to the human. I think they're getting a good deal!