What is the name of the Assassin's Creed film's 15th-century Spanish protagonist?

The Assassin's Creed film's 15th-century Spanish protagonist is Aguilar de Nerha.

Aguilar de Nerha is an Assassin operating in Spain during the Spanish Inquisition. Michael Fassbender portrays Aguilar in the historical sequences and also plays Callum Lynch, his modern-day descendant. The film uses a fictional genetic-memory technology to connect Callum with Aguilar's experiences.

Aguilar belongs to the Assassin Brotherhood and works with fellow Assassins including María. Their mission involves protecting Prince Ahmed of Granada and keeping a powerful Apple of Eden away from the Templars. These historical events provide the film's action narrative within the larger franchise mythology.

Callum Lynch is not Aguilar's alternate name. He is the modern protagonist whose memories are accessed through the Animus. Alan Rikkin is a modern Templar leader, while Liam Millar is another character associated with the film's historical storyline.