Rigagu was an average matoran before he became a toa. He found a toa stone in the ice after failing to make a snow sculpture. He then was kidnapped by rahkshi who lead him to mount rilamu and Makuta Diablos. Makuta Diablos gave Rigagu and Almak three choices. They could either be thrown off a cliff, Fed to giant Takea sharks or having all their breath sucked out of them. He decided to get the air sucked out of him because he had a huge fear of takea sharks and Almak had already decided to be chucked off a cliff. Rigagu survived thanks to his mask of breathlessness. Almak saved Rigagu and began venturing through the inside of mount Rilamu. they reached a small pool inside the ice volcano and found Fernua and Eros unconcious in the water. they than took the two toa and waited for them to regain conciousness. The four toa ventured through the inside of the volcano and reached a small room inside the volcano. below them they felt the snow rumble and were immediately blasted into the air. Fortunately Imaru was flying above the volcano at the same time and caught all four of them. Fernua and Almak on his arms and Eros and Rigagu on his legs. The five toa flew downwards and met Alara down the bottom. She then told them about the Irakushi and the mask of death.
Rigagu controlled the powers of ice and could stop and start snow storms.
Rigagu was armed with nothing except for a knife in his eye. He wore the mask of breathlessness which allowed him to survive without breathing.