I created my BBEG with flavor, and now can't come up with a decent build!

[Twilight Jack]

May I suggest Warlock? It's a sneaky arcane class, whose flavor is 'you have sold your soul to x', which fits perfectly with what you're trying to do. Even better, it can UMD wands perfectly fine. At level 9, he has 12 ranks in UMD, which means he never fails when trying to UMD a wand.

A wonderful build, that one of the players in the group is already employing for his own character. This guy is not supposed to be "just like your character, but higher level," so it pretty much eliminates it as an option.