In Assassin's Creed Mirage, the protagonist who begins as a street thief in Anbar is Basim Ibn Ishaq.
Mirage follows Basim before and during his rise within the Hidden Ones. After leaving Anbar, he travels to ninth-century Baghdad and trains under Roshan at the Hidden Ones' bureau in Alamut. The story focuses on stealth, investigation and targeted assassinations in a more concentrated setting than the large open worlds of several recent entries.
Basim also appears in Assassin's Creed Valhalla, where he is an important character in the Viking-era story. That connection can cause confusion about which game introduces his personal journey. Mirage is specifically his origin-focused adventure, while Valhalla presents him later in the series' chronology and narrative.