Callum Lynch is the modern-day protagonist of the 2016 Assassin's Creed film.
Callum is played by Michael Fassbender and is forced to use the Animus after being recruited by Abstergo Industries. Through the machine, he relives the memories of his ancestor Aguilar de Nerha, an Assassin active in fifteenth-century Spain.
The film uses the same broad fictional concepts as the games, including genetic memories, the Assassin–Templar conflict, and the Animus. However, Callum Lynch is an original film character rather than the game series' recurring modern protagonist, Desmond Miles.
Aguilar is the historical character whose memories Callum experiences. Keeping those two identities separate is important: Callum belongs to the film's present-day storyline, while Aguilar belongs to its historical narrative.