Ox-King
Ox-King (牛魔王 Gyūmaō, lit. "Ox Demon King"), also referred to as Ox-Demon King when his castle was engulfed in flames, is the king of Fire Mountain, as well as the father of Chi-Chi, the father in-law of Goku, the grandfather of Gohan and Goten, and the great grandfather of Pan. He once trained with Goku's adoptive grandfather, Grandpa Gohan, under Master Roshi at the Turtle School.