Mutaito is Muten Roshi and the Tsuru-Sen'nins' teacher. He successfully seals Piccolo Daimaō in the Denshi Jar with his Mafūba technique, but in invoking the attack, he dies from the severe exhaustion of using the move. In the anime, Son Goku actually meets Mutaito and he's the first person in the series to teach Goku about controlling his "ki". In fact, he's the first person to even mention the word, which soon becomes the explanation for the incredible energy techniques used throughout all of the Dragon Ball series.