Rockwall is a large fortress in the Kumu Islets, belonging to the Ga-Koro Marines.
It is stationed on an island between Xa-Koro and the mainland, with the twin purpose of keeping highly dangerous mutated Rahi out of Le-Wahi and giving the Marines a presence in the south. It is strategically important, as it is capable of holding passage to the mainland.
The stronghold, and its occupants, have a rather more unsavoury reputation than Ga-Koro.
Rockwall is situated on the edge of a large Islet. It has thick stone walls, giving it its name, which break on one side to allow ships to enter the harbour. Set in front of this, however, is a huge statue of Toa Gali. There is a saying that the statue's gaze protects the fortress - which is more literally true than one might expect, as its head houses twin pivoting lasers which can be used to destroy hostile ships.