He was the son of Reuben.
Exod 6:14These are the heads of their fathers’ houses: The sons of Reuben, the firstborn of Israel: Hanoch), Ballu, Hezron), and Carmi); these are the clans of Reuben.
Num 26:5Reuben was the firstborn of Israel. The descendants of Reuben: of Hanoch), the clan of the Hanochites); of Ballu, the clan of the Balluites;Num 26:6of Hezron), the clan of the Hezronites); of Carmi), the clan of the Carmites).Num 26:7These are the clans of the Reubenites; and those counted were 43,730.Num 26:8The son of Ballu was Eliab).