First Evil's History
Mythology
The First Evil was the thing that created evil, and it rarely shows its true face. Few had heard of it and even fewer believed in its existence.
Older than humans and the Old Ones, the First Evil was an ancient power that preceded the written word, although it was younger than the Seed of Wonder. According to Beljoxa's Eye, who could see only the past and present, the First had existed long before the birth of the universe itself, and it would continue to exist even after there was nothing left of reality.
Toying with Angel
During Christmas 1998, the First appeared in Sunnydale. It tried to drive the ensouled vampire Angel into killing the Slayer Buffy Summers, by appearing to him as some of the people he had murdered: Daniel, Margaret, Travis, and Jennifer Calendar. The First told Angel that it was responsible for his return from Acathla's dimension and that he could end his sufferings by giving in to his inner demon.
The First did not mind when Angel chose to die in a sunrise instead, either plan would have been a blow to the forces of good. After Buffy's confrontation with the First, she attempted to stop Angel from committing suicide. A rare snowfall then occurred, with the sun remaining unseen for the entire day, thus saving Angel's life and restoring his will to live.
Trying to end the Slayer line
Buffy's death and resurrection in late 2001 disrupted the mystical forces surrounding the Slayer. So, in the following year, the First Evil began its attempt to use this as a catalyst to destroy the Slayer line, which would allow the primordial entity to take over the world and gain corporeal form. This involved assigning his followers, the Harbingers of Death, to track down and eliminate all Potential Slayers, before turning their attention towards Buffy and Faith, thus destroying the line completely.
The First Evil recruited Caleb, a preacher turned serial killer, who took command of the Bringers. They hunted down the chosen line and murdered Potential Slayers around the world. They also persuaded Debbie, an inmate at the Northern California Women's Facility, to attempt to kill Faith with a Bringers' knife, only for Faith to fight her off.
The First also appeared to Andrew Wells in Mexico as Warren Mears, instructing him to buy a Dagger of Lex. The nightmares it brought to Andrew and his friend Jonathan Levinson drove them back to Sunnydale. The First, in its guise as Warren, fooled Andrew into believing that the Trio would live as gods by opening the Seal of Danzalthar, then drove him into murdering Jonathan on the Seal as a sacrifice of blood. However, the sacrifice yielded too little blood because it turned out Jonathan was anemic, as well as small-statured.
Meanwhile, the First took to tormenting the vampire Spike after he had returned with his soul restored. The First used Spike's trauma with his mother to trigger a more feral, bloodthirsty mindset in him, whenever necessary. Its hold on Spike was eventually severed when the vampire was able to overcome the trigger. Beforehand, however, the First took an evening to manifest itself to members of Buffy's Scooby Gang in order to either break their morale or get them out of the picture, besides using Spike to sire a number of vampires. It masqueraded as Joyce Summers in an attempt to drive a wedge between Buffy and her sister Dawn and also appeared to Willow Rosenberg as Cassie, claiming to be a messenger sent by Willow's dead lover Tara Maclay, but went too far as it asked Willow to commit suicide.
The First then launched a campaign against Buffy and her allies. It ordered the Bringers to kidnap Spike, whom it bled over the Seal of Danzalthar to open the Hellmouth and release a Turok-Han, which seemed invincible until Buffy was able to finally slay it. Later, Caleb blew up the Watchers Council headquarters as the Council was in session discussing the First's campaign.
The First made a habit of attempting to shake Buffy and her allies emotionally and mentally. For example, when Willow would attempt to do even a minor spell, the First would take control of her, further goading her fear of her great power.
The First masqueraded as a potential Slayer named Eve, who was previously murdered by the Bringers. It lived in Buffy's home for days in order to destroy the morale of the Potential Slayers and make them question Buffy's leadership. A while later, the First appeared to a Potential named Chloe, talked her into committing suicide, and then taunted the others in Chloe's guise. The First also continued trying to use Andrew as a pawn, unsuccessfully convincing him into shooting the Potential Slayers that began taking up residence in Buffy's home.
Final battle
The First later summoned Caleb to Sunnydale, setting up base at the Shadow Valley Vineyards, where Buffy and the potentials were dealt a brutal defeat at Caleb's hands. Using the Bringers, the First had them excavate the mystical Slayer scythe MĘ” from a rock, while tricking Faith into a trap. When Buffy went to the Vineyards and took the Scythe, the First instructed Caleb to let her go. Buffy then rushed to rescue Faith and the Potential Slayers who had just been in an explosion.
After Buffy split Caleb in half with the Scythe, the First taunted her for being alone, stating that she would die alone as well. This gave Buffy an idea and she determined that she was going to win after all. Buffy asked Willow to use the essence of the Scythe for a Slayer activation spell, activating multiple Potential Slayers worldwide.
Buffy then led a proactive strike on the Turok-Han army within the Hellmouth itself. The First taunted Buffy after she was stabbed through the abdomen, but she quickly recovered and told it to "get out of [her] face." An amulet that Spike was wearing created beams of sunlight, which wiped out every Turok-Han and destroyed the Hellmouth.
The First was never seen after its last encounter with Buffy. Willow described it to be "scrunched," as destroying its army effectively rendered it powerless.
