Black unicorns had coal-black fur and silky manes. Their eyes could be glossy black or burning red. Their distinctive spiraled horns were long and chased with silver. Unlike normal unicorns, they had the sharp teeth of a carnivore.
Black unicorns were crazed, hateful creatures that lived for violence. They delighted in causing pain and suffering and preferred to eat their meals alive. When wild, they enjoyed inflicted pain on anyone and everything around them for the sheer joy of. They especially hated horses and normal unicorns.
However, they were also chaotic, fickle, and concerned for their own safety; it was not unknown for them to flee when the tide of battle turned against them.
Black unicorns, like their more peaceful kin, had multiple magical abilities. Like all unicorns, they could not be magically charmed or held and were immune to poison and to death spells. They continually radiated silence in a 15‑foot (4.6‑meter) radius around them. Three times per day, they could turn invisible, or radiate darkness for 15 feet (4.6 meters) around them. Additionally, if they successfully attacked an opponent with their horn, they could inflict light wounds up to three times each day. Once per day, they could teleport themselves and their riders without risk, but could only teleport while in darkness or shadow. Their teleportation ability did not necessarily affect their rider, however, and the person would sometimes be left behind to fend for herself.
Additionally, black unicorns could see up to 300 feet (91 meters) in complete and even magical darkness. However, they disliked light.
The horn of a black unicorn was poisonous; anyone struck by it risked being paralyzed for as long as three days before dying of heart failure. The horn could be used to make an extremely potent and fast-acting poison that could kill or paralyze the victim. It could also be ground up to make a highly potent contact poison.
Black unicorns were normally solitary but could also be found in small family units dominated by the strongest male or female. They were unnatural carnivores that particularly enjoyed eating humans, elves, horses, and normal unicorns. When found in the wild, they lived in plains and forests. They were not territorial and wandered from place to place, often invisibly.
Black unicorns were created by wizards in Thay, where they were kept as pets and as mounts in elite cavalry units. However, black unicorns would allow themselves to be ridden by any drow or human female of evil morality. They particularly enjoyed serving blackguards.
The process of becoming a black unicorn rider was hazardous: the applicant had to petition the unicorn directly. If they were found acceptable, then the unicorn would serve; if not, then the unicorn would immediately attack.
- James Wyatt and Rob Heinsoo (February 2001). Monster Compendium: Monsters of Faerûn. (Wizards of the Coast), pp. 83–84. ISBN 0-7869-1832-2.
- Michael John Wybo II (February 1993). “Unique Unicorns”. In Roger E. Moore ed. Dragon #190 (TSR, Inc.), pp. 90–94.
- Anthony Pryor (June 1995). “Monstrous Compendium”. In Michele Carter, Doug Stewart eds. Spellbound (TSR, Inc.), p. 15. ISBN 978-0786901395.