Mezlagob was the ecumenopolis homeworld of the semi-humanoid Mezzels. Located in the Mezlag sector of the Unknown Regions, it rose to interplanetary prominence as the capital of the Tetrarchy of Mezlagob. Accumulating enormous wealth from the Tetrarchy's taxation and plundering of its vassal worlds, Mezlagob became the focal point of anger from the Tetrarchy's subjects. Following the Great Liberation, it became a possession of the Golden Empire and lost much of its wealth in reparation payments to formerly exploited worlds.