Osiris was the husband of Isis and father of Horus. His Egyptian name was Asar. Osiris was killed by his brother Set (Typhon), although the details vary from myth to myth. While dead, Isis used her magic to enable Osiris to father a child. Osiris was vindicated before the gods and was given dominion over the underworld. Each Pharaoh who died was identified with Osiris, while the new Pharaoh was identified with Horus. Some Greek identified Osiris with Dionysus.
A Christian Response by Stephen J. Bedard