King Kai – Dragon Ball Z: Battle of Gods
King Kai (界王, Kaiō), or North Kai (北の界王, Kita no Kaiō; lit. “North King of World”), is the king of the North Area. He is Goku’s martial arts teacher and mentor. He later taught Krillin, Yamcha, Tien Shinhan, Piccolo, and Chiaotzu.