Which Assassin's Creed game first introduced the modern protagonist Desmond Miles?

The first Assassin's Creed game introduced the modern protagonist Desmond Miles.

Desmond is abducted by Abstergo Industries and placed in the Animus, where he is forced to relive the genetic memories of his ancestor Altaïr Ibn-La'Ahad. The modern sections alternate with Altaïr's missions during the Third Crusade and establish the series' continuing conflict between the Assassins and Templars.

Desmond remains the modern-day viewpoint character through Assassin's Creed II, Brotherhood, Revelations, and Assassin's Creed III. His role changes as he learns more about the conflict and becomes involved in efforts to prevent a global catastrophe.

Assassin's Creed II is a tempting answer because it greatly expands Desmond's storyline and introduces Ezio, but Desmond had already appeared in the 2007 original. Brotherhood and Revelations continue his arc rather than beginning it.