Beasts of Xvim were creatures, predominantly carnivorous monsters and animals, that had been warped by the malevolent will of the dark god Iyachtu Xvim into soul-devouring harbingers of fear and violence.
The transformation of a creature into a beast of Xvim was precipitated when a tiny piece of Xvim's divine will was placed inside it. This granted the creature new powers, caused its size to increase, and made its eyes glow with an emerald-green light.
Nearly any creature could become a beast of Xvim, although the deity himself preferred beholders, chromatic dragons, cockatrices, lesser devils, dark nagas, the undead, and certain types of animals, namely those with sharp teeth and claws (especially larger black cats and dogs) or those that naturally provoked fear or thoughts of death (such as bats, vultures, or hawks). While these Xvim-touched animals were much weaker than other more monstrous beasts of Xvim, the fact that they were created from ordinary animals meant that they could appear without warning within cities and other places of supposed safety.
Beasts of Xvim had toughness and strength pushing the physical limits of their species, and were incredibly hardy in the face of pain, poison, and fear. They possessed a supernaturally terrifying presence, and could send folk fleeing with a roar or even just a growl. They also possessed the ability to channel their dark god's hatred of good creatures and individuals into a devastating unholy smite.
Perhaps the most terrifying of the Xvim-touched beasts' abilities was their capacity to feed on the soul of a victim. If a beast of Xvim killed a person and consumed their corpse within a day, their life essence would be destroyed and digested into the beast. At that point, the victim could not be brought back to life by anything but the most powerful of magic, and even wishes or miracles only had a one-in-two chance of saving them.
Upon their transformation, beasts of Xvim became devoid of fear and prone to violence. However, rather than make them uncontrollable or berserk, this was balanced by a desire to inflict evil, and Xvim-touched animals gained a cruel intelligence that helped them get close to their victims. Beasts of Xvim almost always hunted alone, but they would do whatever Iyachtu Xvim required of them. They were also known to serve his faithful from time to time.
Beasts of Xvim used their powers to inflict violence on Iyachtu Xvim's enemies, or whatever hapless victim they sighted. Because of the wide variety of creatures that could be corrupted by Xvim's essence, there were few commonalities in the tactics between different individual beasts of Xvim. One common element in combat, however, was that both the beasts' eyes and their attacks were suffused with emerald-green light.
Prior to the Year of Shadows, 1358 DR, Iyachtu Xvim was known to roam the face of Faerûn to carry out the will of his father, Bane. With a mere touch, he had the ability to transform any creature into a green-eyed beast of Xvim to serve him. Following Bane's death during the Time of Troubles, Xvim absorbed part of his father's divine portfolio to become a true god, and bequeathed the power to create the beasts to his Chosen, Fzoul Chembryl, as well as to his most powerful Xvimlar priests.
As Xvim's power increased, beasts of Xvim became more common, and the dark god was said to take great pleasure in the terror they caused in his name. In Year of the Unstrung Harp, 1371 DR, the pet cat of the noble Tchazzam family of Waterdeep transformed into a beast of Xvim, killing the heir and leading the family to forswear cats.
In the Year of Wild Magic, 1372 DR, Bane was reborn from the body of Iyachtu Xvim, destroying him and absorbing his power. While it is not clear what happened to the beasts of Xvim after this, even a century later there were sightings in Haatar-Baen of large, vicious black cats whose eyes glowed emerald green.
- James Wyatt and Rob Heinsoo (February 2001). Monster Compendium: Monsters of Faerûn. (Wizards of the Coast), p. 86. ISBN 0-7869-1832-2.
- James Wyatt and Rob Heinsoo (February 2001). Monster Compendium: Monsters of Faerûn. (Wizards of the Coast), p. 85. ISBN 0-7869-1832-2.
- Julia Martin, Eric L. Boyd (March 1996). Faiths & Avatars. (TSR, Inc), p. 82. ISBN 978-0786903849.
- Julia Martin, Eric L. Boyd (March 1996). Faiths & Avatars. (TSR, Inc), p. 83. ISBN 978-0786903849.
- Ed Greenwood, Sean K. Reynolds, Skip Williams, Rob Heinsoo (June 2001). Forgotten Realms Campaign Setting 3rd edition. (Wizards of the Coast), p. 265. ISBN 0-7869-1836-5.
- Brian R. James (April 2010). “Realmslore: Vaasa”. In Chris Youngs ed. Dungeon #177 (Wizards of the Coast), p. 80.