Ah. Understood.

This leads me to another headscratcher: Vecna is the only known divine darklord, right? I'm pretty sure that gods can't enter the Demiplane of Dread and the dark powers propably couldn't snatch, I don't know, Cyric. It's just... how could the Mists even take a demigod? Bog-standard outsiders cause pressure and shifts in Ravenloft's planar fabric; gods, even a demigod, should have more weight than that.
Just... what's up with that? Would it maybe be better to take Vecna at he point of his imprisonment to be a hero-god?