Ox-Demon King (牛魔王, Gyūmaō) is Chi-Chi's father and king of the Fire Mountain located west outside the Diablo Desert. He's mostly seen as the provider for the Son Family—giving them money so that they can live—and often gives his grandson Gohan gifts (which are basically books). While he is a wealthy, Goku and Gohan make him run through his money due to their literal inhuman appetites, which he can barely provide. He is voiced by Kirbopher15.
It's rumored that An'nin was Ox-King's wife and hence forth Chi-Chi's Mother due to their extremely similar physical appearances.
It's implied that Fortune Teller Baba may share a blood relationship with Ox-Demon King and Chi-Chi's family. Ox-King calls her "mother" in an episode of Dragon Ball Z. However it may have also been an honorary title as in Japan it is considered respectable to refer to your elders as 'grandfather' or 'grandmother' regardless of whether they are related to you or not. Exactly how the two are related is questionable, however, her reaction when she believes Ox-King is killed during the flaming castle dilemma in Dragon Ball may support this.
Other reasons would be her having Goku alive for a day, which she also did for Grandpa Gohan. However, this could be done on account that they wanted to return to Earth. Also, Pan lives to be over one-hundred, appearing to out live both Trunks and Bra who have more Saiyan-blood than she does, which could be from Baba and Roshi's immortality (as Baba even reveals in a FUNimation dub episode of Dragon Ball that their mother is still alive at that time, yelling at Roshi for missing her birthday). Though this family relationship is never fully explained.