A council of gods eventually decided that Horus, as son of Osiris, was the rightful ruler, and Seth was demoted to fighting nocturnal demons. Isis and her supporters warred against Seth for the throne of Egypt.
She also magically conceived a son, Horus.
Isis collected the pieces and magically revived her brother-husband Osiris, who became King of the Underworld. Seth hacked Osiris' body into pieces and scattered them across Egypt, intending to rule Egypt himself. He was then deceived and murdered by his scheming brother Seth, god of chaos. Myth tells how Osiris, the first god-king of Egypt, introduced laws and agriculture to humankind. In this new paradigm Isis took center stage and became the central goddess in the popular religion of the Egyptian people. Eternal life, which had once been viewed as the sole province of the King, came to be seen as the reward for all those willing to submit to the proper cults.
The collapse of the Old Kingdom brought about several sweeping changes in Egyptian religion. But she had been subordinate in the official Egyptian pantheon to deities more intimately connected with the great king, like Ra and Horus. She was a protector of the throne of Egypt, perhaps in some ways the personification of Royal Power. Isis ('Aset' in the native language) had her start as a comparatively minor deity of Egypt.
