Desmond Miles is the modern-day protagonist of the first five main Assassin's Creed games.
Desmond is introduced in the 2007 Assassin's Creed as a former Assassin who is forced to use the Animus, a machine that accesses genetic memories. Through his ancestors' memories, he experiences the lives of Altaïr Ibn-La'Ahad, Ezio Auditore, and Ratonhnhaké:ton.
His modern storyline continues through Assassin's Creed II, Brotherhood, Revelations, and Assassin's Creed III. The arc connects historical adventures to a contemporary conflict involving Abstergo Industries, the Templars, and the impending 2012 catastrophe.
William Miles is Desmond's father and an Assassin leader, not the protagonist. Clay Kaczmarek is another Animus subject whose memories appear in later material, while Warren Vidic is an Abstergo scientist who supervises Desmond's early sessions.