Osiris, also called the Lord of the Duat, was a member of the First Civilization, revered as an Egyptian god of the afterlife, the underworld and death. He was also the partner of Isis.
In legends, Osiris and his partner Isis watched over the Egyptian pharaohs, with Isis using the Piece of Eden known as the Ankh to keep them from harm. However, Osiris died after some time, murdered by his brother Set, causing Isis to be overtaken by grief and pain.
She then attempted to revive Osiris by using the Ankh, but only managed to do so for one night. From the sexual intercourse between the two lovers that night, their son Horus was born.