In the Assassin's Creed series, Desmond Miles relives ancestral memories through the Animus in the first game.
Desmond is abducted by Abstergo Industries and connected to the Animus, a machine that reads genetic memories inherited from his ancestors. In the first game, he experiences the life of Altaïr Ibn-La'Ahad, allowing the modern-day Assassins to investigate the past while pursuing information needed in the present.
The Animus framework links the historical campaigns to a continuing modern-day story. Desmond’s experiences are not ordinary time travel; the series describes them as reconstructed memories carried through DNA.
William Miles is Desmond’s father and a senior Assassin, while Shaun Hastings and Rebecca Crane support later modern-day operations. They are important characters, but they do not fill Desmond’s role as the first game’s Animus subject.