The Animus is the fictional device that lets people relive ancestors' memories in Assassin's Creed.
In the series, the Animus uses genetic memory to reconstruct experiences inherited through a person's ancestry. A modern subject enters the machine and experiences a historical ancestor's life, allowing the narrative to move between contemporary settings and the past.
Desmond Miles is the best-known early Animus subject, reliving the memories of Altaïr Ibn-La'Ahad, Ezio Auditore, and Connor Kenway through different games. Later stories introduce other users, versions, and portable systems.
The Animus is not the same as an Apple of Eden, which is an Isu artifact, or Eagle Vision, which is an Assassin-related perception ability. “Bleeding Effect” describes a consequence of repeated Animus exposure: skills or behaviors from an ancestor may influence the modern user.