Buffy The Vampire Slayer was a cultural phenomenon which followed the exploits of the titular character, Buffy Summers, in her fight against the forces of evil. And in Sunnydale, the town on the Hellmouth, evil manifested itself in all sorts of ways.
There were the regular, monster-of-the-week villains which only appeared in usually one or two episodes, and they were frightening enough on their own. The scarier antagonists were the ones who lasted for a whole season, or longer! But who was the ultimate Buffy Big Bad?
Adam (Season 4)
The concept for Adam was actually pretty cool, and quite disgusting if one really thinks about it. Adam was one of Professor Maggie Walsh's experiments. She combined human and demon body parts and augmented them with advanced technology to make Adam virtually unstoppable.
It wasn't hard to see the likely Frankenstein-esque inspiration behind Adam, especially as he killed his own creator, but as a Buffy villain, he was kind of boring. He didn't even last the entire season, dying in the penultimate episode of Season 4.
The Master (Season 1)
The Master was Buffy's first-ever Big Bad (a season-long antagonist), and as evil villains go, he wasn't that bad. He was one of the oldest vampires in the show's history, and most other vampires seemed to fear and/or respect him.
However, the Master was also a twisted fanatic, even forming the Order of Aurelius to do his bidding. Add to that that he was basically stuck in an underground cave for most of the season, and you have a villain who didn't really do anything noteworthy until the season finale.
The Trio (Season 6)
The Trio consisted of 2 minor characters who had been featured in the series before, and one new character who was so bland that no one remembered him until he became part of the Trio. In essence, Warren, Jonathan and Andrew began life as one of the least impressive Big Bads in the show.
Originally, they just robbed banks using supernatural means and had fun competing against each other. However, when they crossed the line into murder, this is when they got a lot more interesting. With the Trio turning against each other, they finished Season 6 on a narrative high.
Glory (Season 5)
Season 5 was an amazing season, and it put Buffy and the Scooby Gang through their paces like no other season beforehand. This was in thanks to its main villain, Glorificus (Glory for short), who was an insane Hell Goddess intent on getting home to her own dimension.
Although Glory stole every scene she was in, and she genuinely appeared to be unstoppable, this Big Bad was less scary and frightening, and more hilarious and entertaining. Her grand plan was also a little unambitious for a being of her power.
Mayor Richard Wilkins (Season 3)
Mayor Richard Wilkins was the main villain for Season 3 of Buffy The Vampire Slayer and was quite captivating to watch. Unlike the other antagonists that came before him, the Mayor had a very cheerful demeanor and was very polite.
Essentially, he had the personality of a likable 1950s male. He was incredibly charming, even when he was ordering executions or eating a boxful of massive spiders, which completely added to his creep factor. He was not a politician to be trifled with.
Spike & Drusilla (Season 2)
These two vampires first appeared in Season 2, and decided to stick around Sunnydale for a while. Since the only other Big Bad at that point had also been a vampire, there was a worry that Spike and Drusilla wouldn't leave a mark.
However, the couple was totally different from the Master. They were anarchists, and disparaged the Master's fanatical tendencies, killing the Anointed One when he told them off for breaking the rules. Spike and Drusilla were the first Big Bads to have a sense of fun.
Dark Willow (Season 6)
Unlike Spike and Drusilla, Dark Willow's storyline was the complete opposite of fun. Throughout the season, Willow had been struggling with her magic addiction, and had only just begun to reign it in, finally winning back her girlfriend, Tara.
The two had been enjoying their reconciliation when Warren shot and killed Tara in front of Willow. Enraged, Willow absorbed all the dark magic she could find and set off in pursuit of vengeance, pitting Willow against her former friends in the process.
Faith (Season 3)
Faith is one of the most popular characters in Buffy The Vampire Slayer, and one of the most complex. She first appeared in the third episode of Season 3, befriending the Scooby Gang while on the run from a vicious vampire.
While she started off as a protagonist, Faith's trust issues and her role in the death of the Deputy Mayor lead her down a dark path, and she eventually sided with the Mayor. Faith did everything she could to hurt the Scoobies, including almost killing Angel.
The First Evil (Season 7)
Although the First was the main villain of Season 7, it actually appeared in a one-off episode back in Season 3, where it tried to convince Angel to kill himself to weaken the Slayer. In Buffy's final season, there was no better villain than the source of all evil itself.
The First didn't have a physical form, but that didn't make it any less scarier. It took the form of dead people and preyed on the fears and doubts of the Scooby Gang and the Potential Slayers. The First's alliance with Caleb was also one of the creepiest partnerships on television.
Angelus (Season 2)
No other villain could take this spot. Angelus was a brilliant antagonist, not least because of his extremely personal connection to Buffy herself. Buffy dated Angel in Season 2, who was a vampire with a soul. They slept together, which caused Angel to experience a moment of perfect happiness, causing him to lose his soul.
The fact that Buffy had created this Big Bad caused her so much guilt and pain. Angelus was also very creepy, killing Willow's fish, taking pictures of the Scooby Gang sleeping and worst of all, he killed Jenny, Giles's love interest.