Which modern-day character is the descendant of Altaïr and Ezio in Assassin's Creed?

Desmond Miles is the modern-day character descended from both Altaïr Ibn-La'Ahad and Ezio Auditore in Assassin's Creed. His ancestry allows him to access their genetic memories through the Animus.

Desmond is abducted by Abstergo at the beginning of the first game and forced to relive Altaïr's life. He later escapes with members of the modern Assassin Brotherhood and experiences memories belonging to Ezio and another ancestor, Connor Kenway.

Desmond's role is especially important in the first five main games, where his historical experiences support a present-day struggle against the Templars and an approaching global catastrophe. William Miles is Desmond's father, while Warren Vidic is an Abstergo scientist, so neither is the correct answer.