As for the Rumple factor, that’s an interesting way to look at it and not one I’d stopped to consider. But, I guess the question I come back to is…is there really hope for the “devil” after everything he’s done. Lucifer isn’t forgiven; he’s cast into a pit of fire and brimstone (in Rev.)
I think the devil in this case would be whatever the original Dark One power is, and the people whose names are on the dagger are just those who have believed the lies of that dark power. The devil himself doesn’t become a prisoner until the very end of the book.
(Just to put my cards on the table face-up, I’m from a quiet fundamentalist denomination. I don’t want to annoy anyone.)
Gaultheria's fanvids: http://youtube.com/sagethrasher