Basim's surname in Assassin's Creed Mirage is Ibn Ishaq.
The protagonist is Basim Ibn Ishaq, a street thief from ninth-century Anbar who travels to Baghdad and becomes involved with the Hidden Ones. The game follows his training and rise within the organization during the Islamic Golden Age.
Mirage is a prequel to Assassin's Creed Valhalla, where Basim appears as an important character. Its story explores his earlier life and provides additional context for his beliefs, ambitions, and unusual connection to the Isu-related mythology.
Ibn-La'Ahad is Altaïr's surname, Auditore identifies Ezio, and Kenway belongs to the family line that includes Edward, Haytham, and Connor. These names are all associated with major Assassin's Creed protagonists but not with Basim.