Kame Sennin (turtle hermit) is a very old martial arts expert
that rides a turtle called Umigame and is first introduced in Dragon Ball.
He is also called Muten Roshi, or Master Roshi, the 'invincible old master'.
He taught Granpa Gohan, Gyuu Maou, Goku and Krillin martial arts. He invented
the Kamehameha (turtle attack). During the 21st Tenkaichi Budokai, he pretended
to be Jackie Chun, so he could teach the young Goku and Krillin that there
will always be someone stronger than them. He gave Goku a flying cloud called
Kintoun/Nimbus. Muten Roshi lives at Kame House on a small island, where some
of the other characters usually hang out. His sister is Uranai Baba. In DBZ
he remains at Kame House for most of the time, reading dirty magazines and
watching aerobics on TV.