Toa Mahri was the name given to the Toa Inika after their transformation by the Kanohi Ignika into beings capable of surviving underwater. The Toa Mahri were Jaller, Hewkii, Nuparu, Kongu, Matoro, and Hahli. Each Toa Mahri was fitted with special breathing tubes which acted as gills, making it possible for them to breathe water, but not air.
When the power of the Mask of Life struck the six Toa Inika, it transformed them into the undersea warriors known as Toa Mahri. Now able to breathe water only, they had to rely on their skill and their new weapons to fight an aquatic battle against the evil Barraki.