While traveling through the Dreamers' Realm, Buffy came across a doppelgänger of herself, resembling her perfectly aside from darker clothing, white hair, and paler skin. The Dark Slayer proved to be a challenge for Buffy, able to match her every move and use the same weapons. Nonetheless, Buffy managed to defeat it after a hectic battle.
The Dark Slayer had an equal amount of health and slayer power as Buffy and could perform the same attacks as Buffy with the same amount of damage. She also could imitate any weapon that Buffy equiped and use it against her. She was nearly invincible, able to survive stabbing, decapitation and throwing her off the platform would just cause her to return to the surface undamaged. The only way to defeat her was with fire which can be obtained with a hellfire vial.