An Animus mod is an artificial modification of DDS or Helix code to insert, remove, or otherwise modify the output of an Animus environment so that it no longer conforms with the genetic memory from which the code was originally recorded.
Animus modifications could be made for a variety of reasons. For example, the insertion of anachronistic or additional weapons or avatar clothing for entertainment purposes, such as the inclusion of the Unity Sword–a weapon based off of one possessed by Arno Dorian during the late 18th century–into the genetic memories of Shay Cormac, a mid-18th century individual. Abstergo Entertainment took Animus modifications a step further with the release of the video game Liberation in 2012.
Liberation ostensibly followed the memories of Aveline de Grandpré, depicting her "defection" from the Assassins to the Templars, and going to great lengths to portray the latter in a positive manner. In reality, the end product comprised a heavily distorted manipulation of the source material; in response to this, the hacking collective known as Erudito actively worked to re-introduce the truth into the game, allowing the player to view the full extent of Aveline's genetic memories.
Other examples of Animus modifications include the inclusion of individuals like Evie Frye and Bayek into the recorded memories of Kassandra, an individual who predates both by a significant amount of time.
Not all Animus modifications are intentional but instead can be the result of entering a simulation in an agitated state. Such a case happened to Layla Hassan while reliving Bayek's memories in a state of mental and emotional distress. This caused anomalous manifestations of Egyptian deities to spawn within the simulation.
Behind the scenes
The term "Animus mods" applies not only to in-universe alterations, like those depicted in Assassin's Creed III: Liberation and Assassin's Creed: Rebellion (Abstergo Entertainment), or Assassin's Creed: Pirates (Eustace the Monk), but also to additional real-world content provided in-game via the Ubisoft Club or Helix Store. Items downloaded from these locations, like the various outfits that can be worn by Bayek and Kassandra/Alexios in-game, are of dubious canonicity.
- Assassin's Creed III: Liberation (first appearance)
- Assassin's Creed IV: Black Flag
- Assassin's Creed: Pirates
- Assassin's Creed: Rogue
- Assassin's Creed: Identity
- Assassin's Creed: Unity
- Assassin's Creed: Origins
- Assassin's Creed: Odyssey
- Assassin's Creed: Rebellion