Since his grandfather, Sadachika MORI, and his father, Chikahira MORI, followed the Southern Court (Japan) ruled by the Emperor Godaigo and played active roles in Nanjo-so in Echigo Province, a conflict arose within the MORI family.
祖父の毛利貞親、父の毛利親衡は後醍醐天皇の南朝(日本)に従って越後国南条荘にて活躍し、一家で対立することとなる。