|Protodermis Sea Information|
|Primary Residents||A Kanohi Kakama belonging to a (formerly) deceased Toa Mangai, remains of a Brotherhood of Makuta battleship and its army|
|Former Residents||The Kanohi Kraahkan & Kanohi Vahi|
The Protodermis Sea, also called Sliver Sea, was the seemingly endless ocean in which Metru Nui floats.
The Toa Metru crossed it when saving the Matoran from Makuta. During Makuta's battle with Toa Vakama; the Kanohi Vahi, the Mask of Time was knocked into this sea which exposed and changed the Kanohi's color to rusted orange. Sometime later, Vakama managed to retrieve the Vahi.
Much later, Piraka Reidak and the other five Piraka decided to raid Mangaia and discovered the crushed armor once belonged to Makuta Teridax. Reidak attempted to claim the Kanohi Kraahkan, however, the Kanohi defended itself by shooting Shadow energy at him. Enraged, Reidak quickly threw it to the sea. The Kraahkan was later retrieved and briefly worn by Makuta Icarax.
A part of the sea near Metru Nui was occupied by a Brotherhood of Makuta battleship with the Makuta army hoping to besiege the city. However, the battleship was destroyed and the army were all killed by a fierce storm caused by Mata Nui's awaking.