Osiris was the brother/husband of Isis, and the brother of Nepthys and Seth. He was also the father of Horus.
As well as being a god of the dead, Osiris was a god of resurrection and fertility. In fact, the ancient Egyptians believed that Osiris gave them the gift of barley, one of their most important crops.
A large temple was built to honour Osiris at Abydos.