Osiris is the oldest son of the Egyptian god of the Earth, Geb, and the sky goddess Nut. Geb is the son of the elements Tefnut (moisture) and Shu (dryness). He is the father of Osiris, Set, Isis, and Nephthys. Geb was said to be eternally engaged in coitus with Nut, until Shu separated them. Nut’s name means ‘night’ and her title was “She Who Protects,” along with “Mistress Of All.” Osiris was both the husband and brother of Isis, with Horus as being considered his begotten son. He is one of the oldest gods for whom records have survived in the pyramids, and first appears in texts from around 2400 BC; but by then, his cult had already been well-established.
Osiris was indeed the redeemer and the merciful judge of the afterlife, but also the force in the underworld that granted life, including the growth of plant life, and the fertile flooding of the Nile River. The Kings of Egypt were affiliated with Osiris in death so that as Osiris was reborn from the dead, so they would with him, be granted immortaity. Eventually, all men, not just the royal pharaohs, believed they were with Osiris at death. He is usually show as green-skinned and depicted as a pharaoh wearing the Atef crown, the white crown of Egypt with feathers to either side. He is also usually shown, or carved, holding the crook and flail sings that state divine authority in Egyptian kings, though they were unique to Osiris and his own origin-gods and his feet and lower body are wrapped, as if he were already half mummified.