Frostelus

http://upload.wikimedia.org/wikipedia/en/c/ca/Frostelus.jpg Frostelus was a species of Rahi living in icebergs that floated in from the north after the Great Cataclysm. They seemed to be at least semi-sentient, and had a tribal political structure. Long ago, they attacked a Toa fortress, killing all inside but a Toa of Fire named Lhikan.