In 1491, as a friend of the Spanish Brotherhood of Assassins, Diego was tasked to hide and protect Prince Ahmed from the Templars who wanted to use him as a bargaining chip against his father, Sultan Muhammad XII of Granada.
However, the Templars somehow learned of the Prince's whereabouts and sent Ojeda and Ramirez to capture him. Rounding the inhabitants of Diego's village, the Templars and their men searched the houses until they found the hidden boy under the floor of Diego's barn.
Molesting a woman, Ojeda demanded to know which household harbored the boy and Diego bravely came forward, telling the fearsome Templar that he was the sole responsible and that no one else knew. Ojeda then ordered his men to hang Diego's children under his eyes and then to burn down the village. Fortunately, an Assassin rescue team led by Benedicto assaulted the Templars and their soldiers before they could carry on Ojeda's orders.
- Diego is played by Juan Pablo Shuk in the Assassin's Creed movie where he is only credited as "the Father". His name is given in the novelization.