From Halopedia, the Halo wiki
Swarmlord is a Mgalekgolo title in Jul 'Mdama's Covenant that are encountered in Warzone simulations. Swarmlords encountered in War Games include Magsanggalang, Magtanggol, Makipagtunggali and Nakagagalit. Unlike other Mgalekgolo, Swarmlords typically don Ultra-class armor resembling those of Evocati with blue glowing lights and strips. Swarmlords appear as mythic bosses in Warzone simulations.
List of appearances