Master Roshi is the creator of the Kamahamaha Wave.  He may look like an old man, but he is incredibly powerful.  He beat Goku in the first time Goku entered the World Marshal Arts tournament.  He is also Goku's, Krillin's, and Yamcha's teacher.  He is very talented but is very weird at the same time.  He never does anything because he has no time between watch aerobics  and "reading" magazines.