Before becoming a hero, Spike was a villain and it was pretty great. Watching his continued efforts to try and kill Buffy and her friends made for some nail-biting scenes, but his relationship with Buffy solidified him as one of TV's best vampires.

The Gentleman appeared on a Season 4 episode and forced everyone into silence. It made for an exciting episode that forced the Scooby gang to have their wits about them to take the down the new enemy.

Mayor Wilkins was a cunning individual who was on a quest for immortality. Part of what made him so great was his witty one-liners.

Nathan Fillion portrayed Caleb, who turned out to be a charming individual. However, he did not like vampire slayers, so if you're a slayer of vampires, you should probably keep your distance.

Glory wanted to return home and had no qualms about destroying Sunnydale and wiping out the human race. Buffy died saving the world from her. It was heartbreaking.

The Master was a vampire who ruled the Hellmouth. He had the pleasure of killing Buffy on two occasions. Yup, he's scary as hell.

Buffy's boyfriend, Angel, lost his soul and became one of the deadliest vampires in Sunnydale. Without his soul, he was crazy as hell and plotted to destroy the world. Thankfully, he was saved and the character moved over to a spin-off.

The Turok-Han were in cahoots with the First Evil on Season 7. They were stronger than your average vampire and our favorite characters had to fight against them in the series finale.

Faith was introduced as the polar opposite to Buffy and things got strained pretty quickly between them. After snapping and trying to switch bodies with Buffy, she was redeemed and joined the fight against the First Evil.

Dark Willow went into kill mode when Tara was murdered and tried to take the rest of the world down with her. Buffy had a knack for making good characters go bad, but it messed with the dynamics of the show in a good way.