Boško-A153 is the rifleman for SPARTAN team Centurion. Born in 2525 on Bassania, Boško was three years old when the planet was attacked by the genocidal alien conglomerate known as "The Covenant." He was almost killed by a Brute pack that had just murdered his parents, until he was saved by a large individual in green armor. After making it aboard an evacuation transport, Boško was transported to an orphanage on New Harmony, where he lived until he volunteered for the secretive SPARTAN-III Program.