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Scion fell to the zerg during the early stages of their invasion of Aiur. After a failed attack on a zerg cerebrate, Judicator Aldaris declared that the zerg would be overwhelmed with the strength of the protoss, possibly a reflection of the will of the Conclave. It was declared that Scion be retaken by force of arms.
While Praetor Fenix maintained a small force at Antioch in case of counterattack, Executor Artanis led his forces against the zerg that held the province, specifically the forces of the Tiamat and Baelrog broods. The protoss were able to reclaim the province, though at the cost of losing many protoss lives at Antioch to the zerg.