8. Giles
Appeared in: Buffy the Vampire Slayer Rupert Giles: mild-mannered, stuffy British librarian by day, Watcher by night - one who serves as guide and mentor to a vampire slayer. Giles might have originally seemed to be more of the "straight man" in Buffy, where it was easy to see him as just a comic foil while being a little bit of a father figure for Buffy, but by the time season five had rolled around, he had become so much more. Alluded to as "Ripper" in his backstory, Giles came with a dark past despite his firm yet loving nature as Buffy's watcher (thanks in no small part to a fantastic portrayal by Tony Head) - one which, every now and then, would bubble to the surface. Never was this more true than when dealing with old running mate Ethan Rayne, or when ensuring the fallen God Glory would never terrorize the earth again - killing her human counterpart in cold blood, and eliminating her along with him. For Giles, it was a matter of duty over morality, and he made a choice he knew his Slayer would never make in taking an innocent life. That very moment was the payoff of years of subtle hints to Giles' darker side, and it turned the fans on to the idea of a Giles-centric spin-off called Ripper which Joss Whedon spoke publicly of several times - though sadly, to date, the spin-off is nowhere in sight, and Whedon now has bigger things on his plate.