In the Assassin's Creed film, Michael Fassbender plays both Callum Lynch and his ancestor Aguilar de Nerha.
Callum Lynch is a modern prisoner who is recruited by Abstergo Industries for the Animus project. The machine allows him to relive the genetic memories of Aguilar, an Assassin active in 15th-century Spain during the Spanish Inquisition. Fassbender therefore performs two connected roles: a contemporary man confronting his family's hidden past and the historical Assassin whose experiences are being accessed.
The dual casting is central to the film's structure because the modern plot and Aguilar's historical missions unfold in parallel. Callum's memories also connect him to the wider Assassin-Templar conflict, while Abstergo seeks information about the Apple of Eden.
Jeremy Irons plays Alan Rikkin, the head of the Abstergo Foundation, and Ariane Labed plays Maria, an Assassin ally of Aguilar. Fassbender is also one of the film's producers. The film was released in 2016 and is a separate cinematic story rather than a direct adaptation of one particular game.