A human male sergeant served the First Order as a stormtrooper and military officer of the 709th Legion. During the conflict with the Resistance, the sergeant—whose legion deployed to the planet Batuu—accompanied Lieutenant Agnon and several troopers aboard a TIE echelon to Black Spire Outpost. His most notable feature was a long scar around his left eye, with a blue prosthetic in place of where his eye should be.
He later paid a visit to Dok-Ondar's Den of Antiquities, and found a lightsaber purported to have belonged to the late Jedi Master Ki-Adi-Mundi. During this time, he removed his helmet. He then attempted to strong-arm the proprietor, Dok-Ondar, into supplying him with the weapon so that he could ensure the Resistance did not gain any advantages due to its ties to the Jedi Order. Unbeknownst to him, however, he had been secretly monitored by a video droid that Remex Io of the Kendoh Gang secretly placed among the store's wares, with everything he said having been monitored by them.
The sergeant later left Batuu to brief Lieutenant Agnon regarding their mission on the planet, although he was forced to depart earlier than expected when his squad requested his assistance in dispatching two enemies suspected to be Resistance agents, especially after they killed one of their squad. He was unimpressed when he learned that only two agents gave his men trouble before nonetheless eliminating them with a 125-Z treadspeeder bike, making clear in response to their statement that they'd rather kill the other Stormtroopers than be sent to a First Order prison that the 709th had no intention of taking them alive anyway. After killing them, he then deduced they were not actually affiliated with the Resistance and considered it a waste, also making clear to his forces when asked that he knew this because they barely even put up a fight against him, which a resistance member would have been much more aggressive when cornered. However, he then got an urgent message citing three individuals with death marks issued by the First Order being spotted near the spaceport, with the sergeant likewise telling him to have their informant tail them in case they leave before having the squad depart from the immediate area, citing there's nothing there requiring their presence. Unbeknownst to the sergeant, however, a Resistance agent had overheard his statement.
The sergeant eventually tracked down Kendoh Voss's gang and cornered them at Dok-Odnar's shop, and promptly had RS-2112 smack Wooro with his baton as a form of intimidation towards Voss. However, he was ultimately forced to let them escape after Voss proceeded to destroy the containment field of a baby sarlacc, which resulted in ZJ-7199's demise.