Originally Posted by CM
Sayak is the Arch-Mage of the College with no ties to the Dark Brotherhood and Karliah is a character that's already in the game who is a Nightingale, ties with the Thieves Guild and not the Brotherhood. Only Eclipse and Agana are the only ones who are in the assassins guild other than the characters who are in game.
Ah, I stand corrected. Fishysticks (if you followed the Elder Scrolls since Morrowind, you will get the reference).