In the original Assassin's Creed, which Animus subject relives Altaïr's memories?

Desmond Miles is the Animus subject who relives Altaïr's memories in the original Assassin's Creed. Abstergo Industries abducts Desmond and uses the Animus to access genetic memories inherited from his Assassin ancestor.

The Animus frames the historical sections of the game. Desmond remains in a laboratory in the present day while the machine reconstructs Altaïr's experiences in 1191. This structure lets the story move between the medieval Holy Land and a modern conspiracy involving Abstergo and the Templars.

Several other characters are connected to the Animus across the series. William Miles is Desmond's father, Clay Kaczmarek is another important subject, and Daniel Cross is a Templar operative. They are therefore plausible names in the broader lore, but Desmond is the subject in the first game.