That was interesting - mortal vampires, who fed only from willing victims. Not a concept Schmendrick had heard of before, and Schmendrick had heard many strange things in his time. Still, he felt he could understand some of what else the man was going through.
"Any magic that's worth anything has a price," Schmendrick said solemnly. "Sometimes the price is clear. Oftentimes it is less well known." For example, his wizardry that had turned the unicorn into a human and back again had had a heavy price paid by them both, yet one that was difficult to put into words. "It's up to us to decide if the magic's gift is worth its cost. If I were to guess, I'd say you decided once that it was, and now you're having second thoughts."
It reminded Schmendrick in some way of his own curse. When he'd first been gifted with life until he mastered his magic, it had seemed a blessing; but with time, as magic had refused again and again to do as he wished, as those he loved had aged and died, he had wished at times that he had never sought to pursue magic in the first place.