Zivon

Zivon is an enormous Rahi of which only one specimen has been found. It inhabits the Zone of Darkness, and can be summoned by the Kargarak, though most Visorak would prefer not to ally with it, as it usually devours most of its allies as a victory meal. The Zivon is extremely powerful, even the Toa Hordika could not defeat it. Its Rhotuka can blind, deafen, mute, and numb enemies if they hit them. Zivon is, nevetheless, extremely valuable to the Horde, as it is virtually undefeatable. It was last seen vanishing into the Zone of Darkness with Krakua and a Tahtorak.

Behind the Sets
One can create Zivon by combining pieces from Vohtarak, Boggarak, Keelarak, Suukorak, Roporak, and Oohnorak sets.