Guardian (Boss)
From Wikitroid, the Metroid wiki
In Metroid Prime 2: Echoes, a Guardian is the boss of an area and guards its Dark Temple. There are three Guardians, in Dark Agon, Dark Torvus, and the Ing Hive:
There are also sub-bosses named Sub-Guardians, who are or are possessed by the Ing who stole Samus's power-ups at the beginning of the game:
