Karlsu was a male Human who served in the Republic Military during the Cold War with the Sith Empire. A Lieutenant stationed at Waypoint Station Aurek on Taris, Karlsu was part of a commando team sent to escort researchers into the wreckage of the Republic warship the Endar Spire. The only survivor of his team, Karlsu aided a Republic-allied individual sent by Captain Childress in defeating the pirate forces within the ruined ship.