Special Operations Group One, also known as Operations Group One, was one of five Special Operations groups sent by the reconstituted Sith Empire into the Belsavis prison during the Invasion of Belsavis during the Galactic War in hopes of locating and freeing the Dread Masters. Led by the Sith Lord Andreaus Thos, Operations Group One was successful in breaching the section of the prison known as the Tomb with the aid of Special Operations Group Two, and Group Two established a base camp while Group One continued into the Tomb—but the Imperials unleashed the savage Esh-kha species from their stasis, and suffered heavy losses. Part of Group One located the Dread Masters in Vault 914 but were killed by the Esh-kha, and Thos led another part of the group to stasis block 44 to free other Sith prisoners, but his forces suffered heavy losses at the hands of the Republic.