A darkenbeast, also called a death horror or dark horror, was an artificial magical beast created by evil spellcasters. They were transformed from ordinary animals into terrifying monsters loyal to their master's will.
|“||The darkenbeast circled the campsite again, its dark spirits soaring now that its quarry was at last alone. It pulled its wings close to its body, plummeting like a rock and crying loudly as it separated from a low-hanging cloud. The sound was a peculiar, irritating shriek that sent shivers racing down Galvin’s back and brought him unsteadily to his feet. The druid was familiar with thousands of animals, but he had never seen the likes of this beast. It stank of sorcery.||”|
Darkenbeasts were 3–5 ft (0.9–1.5 meters) long and had wings that could extend to twice the length of their bodies, ranging from 6–10 ft (1.8–3.0 meters). Their reptilian bodies resembled a cross between a small wyvern and a pteranodon, with constraining black hides that exposed a glowing skeleton ranging from green to purple. Their heads were balanced on curved necks that hosted long flickering tongues, and dimly glowing red eyes. Their mouths were filled with fangs and their first wing joints hosted a keen pair of claws. No two death horrors looked alike, as minor vestiges of the animal's original form remained. Some of the darkenbeasts' bones were luminous like their eyes and showed through their skin.
Darkenbeasts were almost completely loyal to their creators and followed their commands to the best of their ability, even if said action would result in certain death. The only exception to this was if ordered to attack their original master. Darkenbeasts ordered to commit violence against their masters might break free of the spell's control, staying in their new form but acting normally and following their normal masters.
The darkenbeast dived down from the air, attacking their target with a combination of fang and talon. They were immune to any form of mental magic, only obeying the telepathic commands of the caster, who gave limited orders based on mental images. They were remarkably durable and treated themselves as expendable during any combat situation, requiring their masters to consciously pull them out of pointless melee. At the point of creation, a spellcaster could imprint a spell into the death horror's being, allowing them to cast the spell if the creature was nearby. This process had a 25% chance of killing the death horror, increasing if more darkenbeasts were imprinted by 10%. Regardless of the spell's success or failure, a darkenbeast with its spell evoked would die in a spout of magical purple flame, causing them to revert to their true form.
A darkenbeast was born when a mage cast a create darkenbeast spell on a normal animal. Darkenbeasts could not exist where there was light, requiring the spell to be cast in darkness. Death horrors exposed to light from the sun or a daylight spell could revert to normal at almost any moment, with the power of a sunbeam spell instantly dispelling the transformation. This could also be accomplished through dispelling magic, as well as killing the darkenbeast, although the latter also killed the true animal. No matter what their true forms were, darkenbeasts were always carnivorous. Mages in the Underdark were known to keep packs of darkenbeasts permanently. 
Circa 1362 DR a Red Wizard Maligor used alteration magic to shapeshift hundreds if not thousands of animals into darkenbeasts to be used as bloodhounds; the components for the spell included verbal and somatic components, a moonstone focus, and dried wyvern blood as the material component.
- ↑ 1.0 1.1 1.2 1.3 Scott Fitzgerald Gray (April 29, 2014). Dead in Thay. (Wizards of the Coast), p. 81.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 James Wyatt and Rob Heinsoo (February 2001). Monster Compendium: Monsters of Faerûn. (Wizards of the Coast), p. 30. ISBN 0-7869-1832-2.
- ↑ 3.0 3.1 3.2 3.3 3.4 David Cook, Steve Winter, and Jon Pickens (1989). Monstrous Compendium Volume Three Forgotten Realms Appendix (MC3). (TSR, Inc), p. 16. ISBN 0-88038-769-6.
- ↑ Ed Greenwood (1991). The Ruins of Undermountain. (TSR, Inc.), p. Cannot cite page numbers from this product. ISBN 1-5607-6061-3.
- ↑ Jean Rabe (1991). Red Magic. (TSR, Inc.), p. 32. ISBN 1-5607-6118-0.
- ↑ Jean Rabe (1991). Red Magic. (TSR, Inc.), p. 11. ISBN 1-5607-6118-0.
- ↑ Jim Butler (1995). The Secret of Spiderhaunt. (TSR, Inc), p. 7. ISBN 978-0786901500.