Osiris was the god of the underworld and the ruler of predynastic Egypt. The son of Geb and Nut. Osiris also had a brother. Set, and a sister Isis (who he married). Unlike his evil brother, Osiris was benevolent towards humanity, teaching people the ways of agriculture and aiding the founding of Egyptian civilization.
According to one popular myth, the jealous Set killed Osiris and divided his body into fourteen pieces which he scattered across Egypt. Isis eventually found all the pieces. According to one version of the myth, Isis merely buried all the pieces where she found them, but another myth tells that she brought the pieces back together and revived Osisris.
Osiris also had a son, Horus, who killed Set and took his rightful place as ruler of Egypt, while Osiris took place as ruler of the underworld.