Geb was the husband and brother of the sky goddess Nut and the father of Osiris , Isis , Nephthys and Seth . When Seth and Horus ( Osiris ' son ) fought to become the king of Egypt , Geb made Horus the ruler of the living . In mythology Geb also often occurs as a primeval divine king of Egypt from whom his ` son ' Osiris and his ` grand-son ' Horus inherited the land after many contendings with the disruptive god Seth , brother and killer of Osiris .