He's the oldest son of Geb, god of the earth, and Nut, goddess of the sky. He's also the brother of Seth and Nephthys.
Consorts & Children:
He's the brother-husband of Isis, and through her, father of Horus. He's also possibly the father of Anubis, through his sister Nephthys.
He's often depicted as a man with green skin, holding a shepherd's crook in one hand and a flail in the other, and wearing a crown with an ostrich feather on either side of it.
Notable Stories Involving Him:
Before taking over as god of the underworld, he was killed and dismembered by his brother Seth, who'd tricked him into a box that had been fitted to Osiris's measurements. His wife Isis then found his dismembered body, reassembled him (except for his phallus, which was eaten by a fish), and resurrected him.
Osiris Around the World:
His equivalents are Hades and Pluto, the Greek and Roman gods of the Underworld, respectively.
SOURCES: Wikipedia and Encyclopedia Mythica