Thi was a member of the broadly peaceful Desert Pearl people of the Tuskens on Tatooine. Five years before the start of the campaign, he left home to gather black melons, and when he found his way back his village was set aflame, his brother, mother, sisters, father and nephew all dead. He went on a tear to find the cause of this tragedy, and discovered that his people were murdered as part of a weapon's test. He has since been climbing the ranks of the rebellion, attaining the status of Commander and the nickname of “The Terminator.” During the battle of Scarif, Thi was placed in command of the Tantive IV, and barely was able to flee with the Death Star plans. As Vader's Fist and Darth Natus boarded the ship in orbit of Carlac, he sent the plans planetside in an escape pod, contained in a single droid, before being captured and brought to the Death Star for interrogation.

Thi’s existence is defined by an all-consuming need for vengeance against the Empire for the destruction of the Sand Pearl people. In particular, he hunts the commander who approved of the weapons test that was used upon them.

Thi is a male Tusken with a powerful build and unknown facial features, though he does seem near-human judging from his features from the neck down. In the interests of his goals, he foregoes traditional Tusken robes, though he does still keep them and wear the mask. He wears a primarily synthleather rebel outfit, consisting of shirt, pants, vest, backpack and boots. He has his Gaffi stick on the left side of his backpack, and the rifle parts of his blaster on the right side when not in use.