Rosetta Anastasia is a Battle Sister of the Order of the Ermine Mantle and was raised at the Antigone's Harbour Schola Progenium on Terra. Upon joining the Ermine Mantle, Anastasia left Terra for the Hive World Subiaco Diablo, where the Order's convent is based. The Hive World was later ravaged by the Plague Zombie virus, during the 13th Black Crusade and the Ermine Mantle's Battle Sisters fought against the undead hordes the virus created. All save Anastasia herself, however, as she became afflicted with a fever that prevented her from fighting. While the Plague Zombies were eventually repelled, many of Anastasia's Sisters were killed in the battle before they emerged victorious. Their deaths moved Anastasia to invoke the Oath of the Penitent and she become a Sister Repentia, for failing to fight alongside her Sisters, as well as against the blight that had tainted her.