Mutaito was the master of both Muten Roshi and the Crane Hermits, making him one of the earliest and most influential teachers in the series. He's best known for developing the Mafūba—a sealing technique powerful enough to trap the demon king Piccolo Daimaō in the Denshi Jar. The move came at a cost: the technique drained him so completely that he died from the exhaustion.
In the anime, Goku actually trained under Mutaito at one point, and fans often note that he deserves credit for introducing the concept of "ki" to the series. Before Mutaito, there was no real framework for explaining the wild energy attacks that would eventually define Dragon Ball's combat system. He was the first to put a name to it, and that single concept ended up shaping how the entire franchise understood power and technique going forward.
Content compiled by AnimeList.moe from publicly available sources.
