She was selected for a great honour - a position aboard the Gloriana Class Battleship Adamant Resolve, the XII Legion's flagship. Andrasta served as the vessel's Navigator throughout the Great Crusade, seeing numerous changes within the Legion over the years. In particular, she witnessed the Legion change from the War Hounds to the World Eaters after reuniting with their Primarch, Angron. By the end of her service, even the ship's name had been changed from the Adamant Resolve to the Conqueror.
Andrasta still served on the ship at the outbreak of the Horus Heresy, when she was ordered to guide the Conqueror towards Terra in preparation for the oncoming battle. Ultimately, however, she remained an Imperial Loyalist. One night, while the ships were in transit through the Warp, she committed suicide with a laspistol.