I think a beguiler would make a great BBEG... you'd never be able to pin down who it was that was doing all the evil things. It would be so easy for him to set up a patsy and not leave fingerprints. If he did get foiled, he'd just need to be able to walk away and start again.
An elf beguiler would be something to contend with. His long, long time horizon means this guy is going to be methodical and careful. Contingencies within contingencies would be meet any party of PCs looking to stop whatever nefarious plans he might have.
He'd be less effective in combat, but almost unparalleled at escaping and avoiding combat: I can't think of a more irritating BBEG to face than one you can't pin down.
An elf beguiler would be something to contend with. His long, long time horizon means this guy is going to be methodical and careful. Contingencies within contingencies would be meet any party of PCs looking to stop whatever nefarious plans he might have.
He'd be less effective in combat, but almost unparalleled at escaping and avoiding combat: I can't think of a more irritating BBEG to face than one you can't pin down.