Master Roshi(otherwise known as Kame Sennin) was the trainer of Goku and Krillin, but now he cant fight as good as he could since he is real old, like 300 years old. He taught all of the Z-Warriors the Kamehameha. Which is one of the strongest attacks they have. Goten and Trunks can combine their energy for the Kamehameha and make it a 2xKamehameha. Master Roshi is old and wrinkled, but he can still dish out some power from his old hands.He lives on a island WAY out in the ocean isolated from all civilization kind of.