In the World of Greyhawk campaign setting for the Dungeons & Dragons roleplaying game, an Animus is an undead monster created through the use of both arcane and divine magic. They are unique to the Great Kingdom and its successor states.
|Source books||From the Ashes, W:Ivid the Undying|
|First appearance||From the Ashes|
Animi retain all skills and powers that they possessed in life (unless a deity forbids it) and also attain other powers from their transformation. All animi possess immense strength, and can spread fear by their touch. They also gain the power to command undead, and can paralyze by gazing into a target's eyes. An Animus can also mentally dominate living creatures and implant suggestions into their minds.
Among the most important powers of an animus is its regeneration powers. An animus can only be destroyed totally by being cremated or dissolved in acid.
Unique among undead, animi are affected by disease. However, as the animus is already dead, no disease can be fatal or terminal to an animus.
The animus first appeared in From the Ashes, which linked the first appearance of the monster to the Greyhawk Wars storyline. The idea was fleshed out in the never-released (but available online) supplement Ivid the Undying. The monster was later updated in 2001 for third edition in the Living Greyhawk Journal, and for 3.5 in Dragon Magazine's "Creature Catalogue" feature.
There have been no official game stats allowing players to replicate the process of creating animi, and it is explicitly said that the process would be impossible to replicate in game statistics. 
The animi are a legacy of the alliance between the House of Naelax and the devil Baalzephon. In the 440s CY, an ancestor to the Naelax line of Overkings made contact with Baalzephon to further his own powerbase. Baalzephon promised to aid the Naelax in gaining the position of Overking in exchange for the souls of the Naelax line. Part of this aid rendered would be the secrets to making animi.
Around 583 CY, during the Greyhawk Wars, the first animi were created. Overking Ivid V, paranoid about disloyal advisers and nobles, had numerous key generals, nobles and lords assassinated, particularly after the defeat of Aerdy forces at the Battle of Innspa. Their bodies were handed over to priests of Hextor and pit fiends supplied by Baalzephon. Each body was imbued with an admixture of divine and fiendish arcane spells while the body resided in an artifact on loan from Baalzephon, the Casket of Abyssal Bone.
Amongst those transformed into animi was, eventually, Ivid himself, transformed on the orders of Baalzephon, who hoped to stave off the wasting disease that had afflicted Ivid and threatened to kill him. The aim was to keep Ivid as a stable puppet on the Malachite Thron. The plan failed, however, as the disease progressed unchecked.
Since the loss of Rauxes and with it Ivid, there have been no means to create new animi, as Baalzephon's devils and the Casket have vanished along with the capital of the Great Kingdom. The exact spells used to create animi have also been lost as well. However, numerous animi still walk the lands of the Aerdi. Since Ivid's disappearance, the magical effects that bound them to loyalty to him were diminished, and many of the animi pursue their own plans.
A second story places the blame of the creation of the animi, at least initially, on W:Lady Lorana Kath, one of the 12 Death Knights created by Demogorgon. In this telling, she created the first Animi from peasantry from her fiefdom near Stringen, either as a means of finding a lover who could tolerate being near a Death Knight, or in the hopes of finding a way of undoing the transformation imposed upon her by Demogorgon. She later revealed the secret of animus creation to Ivid V and the priesthood of Hextor as a means of currying favor. Under this theory, Kath is thought to be still capable of creating new animi, a potential that she uses as a means of retaining power within the priesthood of Hextor. 
- Prince Anxann
- Darrien of Dastryth
- Delglath of Rinloru, who can secrete acid from his palms
- Drax the Invulnerable, Ruler of Rel Astra
- Prince Hastern
- Overking Ivid V
- Prince Jichrisen
- Prince Kalord
- General Kalreth
- Prince Kobasten
- Count Madral Ishenvan of Paralad
- Marrin of Errantkeep
- Duke Szeffrin of Almor, said to have been given iron-like skin during his transformation
- Prince Zamasken
- Sargent, Carl. From the Ashes (TSR, 1992)
- Sargent, Carl. Ivid the Undying (TSR, unpublished). Available online: 
- Reynolds, Sean K. "Enchiridion of the Fiend-Sage." Living Greyhawk Journal #2 (Paizo Publishing, 2001)
- Reynolds, Sean K. "Creature Catalogue IV: Campaign Classics." Dragon #339 (Paizo Publishing, 2006)
- Ivid p. 32
- Holian, Gary. "The Death Knights of Oerth, Part Two." Dragon Magazine #291 (January, 2002), page 95. Paizo Publishing, 2002.