A character that appears in Halo 3 only during 4-player co-op. Usze (nicknamed "Uzi" by fans) is controlled by player four.
His official Bungie bio (Which is the extent of his backstory):
Although Usze ‘Taham was born into a respected merchant family he was fathered by Toha ‘Sumai—one of the preeminent swordfighters of this age. Usze graduated with honors from the top War College in the Iruiru region of Yermo, Sanghelios (a distinction he shares with Rtas 'Vadum). Shortly after receiving his first post within the Covenant Navy he was offered a place on the Prophets’ Honor Guard but he declined citing “lack of practical experience”. In truth, he had no desire to be part of a largely ceremonial unit, and at the end of his third combat tour, Usze ‘Taham again refused the post—even though his superiors warned him such behavior could be misinterpreted as apostasy.
Since that time Usze has evaded countless punitive actions, at least two assassination attempts, and served with distinction for two additional tours before the Schism. Following the dissolution of the Covenant, he was approached by the Ascetics to become one of their liaisons within the Navy.