Miles is the surname of Desmond, the modern-day protagonist in the early Assassin's Creed games.
Desmond Miles is a descendant of several important historical Assassins, including Altaïr Ibn-La'Ahad, Ezio Auditore, and Ratonhnhaké:ton. Abstergo Industries captures him and uses the Animus to access his genetic memories, making him the link between the modern storyline and the historical campaigns.
Desmond appears as the modern-day playable character in the first five main games, although the amount of direct control varies. His journey is especially prominent in Assassin's Creed, Assassin's Creed II, Brotherhood, Revelations, and Assassin's Creed III. The names Auditore and Kenway belong to historical characters in his ancestry, not to Desmond himself.