While on a journey in the tundra, the ground collapsed from beneath he feet and he fell into a huge deposit of Thermal energy. He was instantly morphed into a big and stronger toa. He still has the powers of a ice toa but he can raise his body temperatures to amazing hot temperatures. He can also us the thermal energy in him to be a replacement fuel for things that need some form of fuel to make them work. When he slashes anything with his thermal blade the objects temperature will raise and evenutally cause death. A average makuta would instantly die within about 5 mins. So I guess he is a toa of ice and thermal energy now.