Out of all the villains featured in Buffy the Vampire Slayer and the extended Buffyverse, Angelus is by far the worst. Angelus is the original form of Buffy's primary love interest, Angel, and is considered to be one of the most evil vampires to ever exist. Angelus' appearances in Buffy and spin-off Angel created an unpredictable level of chaos that solidified him as a great villain.

Before his on-screen debut in season 2, Angelus was first mentioned in the first season of Buffy the Vampire Slayer. Prior to becoming Angelus, he was a human called Liam, who was born in Galway, Ireland, in 1727. After a night of drinking, Liam gets into an argument with his family, prompting him to leave his house in a rage. To deal with his anger, Liam went to a tavern where he got into a fight; after getting kicked out, he met Darla, a vampire who promised him the world of his dreams and sired him. Following this, Liam became Angelus, one of the most ruthless vampires in history who massacred his own family. Angelus continued his massacre all through Europe, but after killing a Roma's daughter, he became cursed with a soul that led him to become Angel.

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Angelus's transformation into Angel left the latter with an incredulous amount of guilt for the pain and suffering he had inflicted on others for over 100 years. Angel went on to be rejected by Darla, who was unwilling to accept his newfound humanity. Following this, Angel lived a peaceful life, teaching himself to fight the urge to feed on humans. Angel spent years keeping that evil that was Angelus at bay, with the curse only able to be broken by a moment of pure happiness. But, of course, through factors such as his relationship with Buffy Summers, Angel does experience pure happiness, unleashing Angelus several times.

Angelus Is Unleashed

Angelus talks to Buffy Summers.

Angelus first appears in Buffy the Vampire Slayer season 2, episode 22, "Becoming (Part 2)" after he experiences a moment of pure happiness when he has sex with Buffy. With Buffy and Angel's relationship acting as a massive catalyst for season 2 due to their forbidden romance, his sudden turn into the evil Angelus forced Buffy's life to take a drastic turn in the most heartbreaking way possible.

Upon his release, Angelus joins Spike and Drusilla in their plot to release the Judge. However, Buffy stops the trio in their plans, which leads Angelus to target Buffy sadistically. Angry that Buffy caused him to fall in love, he begins to torture her loved ones, even making a necklace out of Willow's dead fish. Angelus also kills Roma woman, Jenny Calendar, after learning that she was planning to ensoul him again. Angelus then sets out to open a portal to Hell but is stopped by Buffy, Spike, and Willow, who restore his soul once again. However, the portal was already opened, and Angelus had to die to close it. Buffy, placing her Vampire Slayer responsibilities first, then stabs him with a sword and kicks him through the portal, closing it once more.

Eventually, Angel is able to escape from Hell and, over time, regains his memory of Buffy and Sunnydale. However, while Angel does not lose his soul and turn back into Angelus for the remainder of Buffy, he is continuously tormented by the evil presence within himself, with Angelus always whispering in his ear, attempting to coax out his dark side.

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Rebecca Drugs Angel With Eternal Bliss

Angelus on Buffy

Years later, in Angel season 1, episode 17, "Eternity" after Angelus's initial return, Angel moves to Los Angeles to isolate himself from humanity. However, while he is there, he meets a young actress named Rebecca Lowell in Angel's first season, who he forms a close relationship with after her team seeks out Angel Investigations for help with a stalker. After a masked man breaks into Rebecca's house during a party, Angel jumps to her aid, where Rebecca notices he has no reflection, discovering that he is a vampire.

However, Angel does not realize that Rebecca is eager to become a vampire herself due to her desire to be eternally young. Rebecca goes shopping with Angel's close friend and co-worker, Cordelia Chase, to obtain more information about him. Later that evening, Rebecca visits Angel and spikes him with a drug that simulates bliss to convince him to turn her into a vampire. However, as the drug causes Angel to feel pure happiness, Angelus is unleashed again, and he attacks Rebecca attempting to kill her.

Rebecca escapes and seeks the aid of Cordelia Chase and Wesley, who deduces that Angelus will revert to Angel once the drug has worn off. Angelus arrives and begins mocking both Cordelia and Wesley, revealing harsh truths about the pair. After Cordelia tricks Angelus with fake Holy water, Wesley knocks Angelus out by pushing him down an elevator shaft. Angel then wakes free from Angelus, where Cordelia is annoyed that he can only be honest as Angelus. Cordelia then leaves Angel tied to a bed until she can trust he truly has his soul back again.

The Arrival Of The Beast

Angel and Angelus square off on Angel

For a few years, Angel was able to keep Angelus at bay. Finally, however, the fourth season of Angel saw the arrival of the mighty demon known as the Beast in Los Angeles. The Beast first arrives on Earth at the birthplace of Angel's son, Connor, and is set to bring about the beginning of the apocalypse. Angel and his team believe that the only way to destroy the Beast is to strip Angel of his soul and revert to Angelus once more, due to the fact that Cordelia had a vision that Angelus had fought the Beast before. Unfortunately, Angel could not remember this encounter, as a spell had been cast before the Beast arrived that erased all references to his existence, with only Angelus unaffected.

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When Angelus is freed in Angel season 4, episode 10, "Awakening", he is convinced to reveal details about his initial encounter with the Beast, where he states he did not aid in the Beast's initial banishment in 1767. After Angel's soul is stolen and cannot be restored, Angelus seeks the Beast out, where he then defeats it with the help of Wesley and Faith. However, the defeat of the Beast brings the sun back, and Angel's soul is again restored after a brief mental duel between Angel and Angelus. Following this, Angelus is never featured in the world of Buffy the Vampire Slayer again, with Angel keeping his soul for the remainder of the spin-off show Angel.