Hmmm...okay! I got another one. What if he could only feed from one person at a time. Like, until their dying day, they were it. The only person he could feed off of until they died.
Now THERE’S a curse for your fucking enemies. Oh my god. Just like the soulmate thing, but in horrifying reverse. People offering up a sacrificial dipshit every generation to the Jean in the Mountain.
Imagine being a guy who broke a woman’s heart then belittled her for crying afterwards. Witch sees you do it and curses you to be Jean’s fucking You Only Get One, just, congratulations, now you have this immortal, intensely powerful being feeding off your emotions for the rest of your life, just learning every little button you have and inventing new ones to implant in you when he’s bored. And you can never escape, because he needs you to live and would never let you get away. Just an entire lifetime of having your emotions manipulated and exploited by this fuckin’ asshole, and the only way you can get out is to die.
He probably goes through ‘em pretty fast.