Muten Roshi, also known as the Turtle Hermit (Kame Sennin), is a legendary martial arts master in the Dragon Ball series. Renowned for his wisdom and perverted humor, he is the founder of the Turtle School and the original teacher of Goku, Krillin, and several other key characters. Despite his old age and comical demeanor, Roshi is a formidable fighter and plays a crucial mentor role, guiding the main characters throughout their early adventures.