Agrellan

Agrellan is the Imperial hive the T'au took in a day, renamed Mu'gulath Bay, and used as the Third Sphere gate into the Dovar cluster. After Prefectia the Imperium came back hard; the T'au held until Exterminatus burned the sept, one shielded city excepted, and the Damocles Gulf was set alight. One pin, two names. Not Prefectia.