He is a former Librarian and hates his old Legion, the Blood Angels.[3a] Ison keeps his Legion's origin a secret, finding amusement in irritating Macer Varren by refusing to answer which he originated from. Ison fought alongside Varren, Nathaniel Garro, Tylos Rubio, and Helig Gallor against Chaos Cultists on Terra.
After the battle against the Lord of the Flies and his minions, Ison was among those chosen by Malcador to join his new order. Ison took on the title Satre, who would go on to become one of the original founders of the Grey Knights.[3b]
Satre was an Etruscan God associated with Saturn in Roman culture and Kronos in Greek culture.