Set is the Egyptian god of war, chaos and storms. He is basically the god of evil as he is the villain who stood for everything the Egyptians feared and hated: disorder, chaos, waste, drought, famine, destruction, hunger, and foreign invasion/influence.
He is the brother of Osiris, Isis, and uncle to Horus, and brother as well as husband to Nephthys. His other consort was the goddess Tawaret, a hippo-headed deity who presided over fertility and childbirth. He is one of the first five gods created by the union of Geb (earth) and Nut (sky) after the creation of the world.
As first-born, Osiris was elevated as ruler of the world which, to the Egyptians, meant the land of Egypt. Set grew jealous of Osiris' power and resented his success. His resentment grew more bitter after his wife Nephthys, attracted by Osiris' beauty, disguised herself as Isis and seduced the great king, becoming pregnant with the god Anubis. Set decided to remove his brother and had a magnificent casket created, the most beautiful chest ever made, tailored to Osiris' exact measurements.
He threw a grand party, to which Osiris was invited, and after the banquet told the guests he had a special surprise. He revealed the chest and said that whoever could fit most perfectly inside could take it home. One by one the guests climbed into the casket but could not fit until Osiris' turn came. He lay down in the casket and found, of course, that it fit him perfectly. Set then slammed the lid on and threw the casket into the Nile River. Set took the throne, and the harmonious balance which had been maintained by Osiris and Isis was lost. Set was a chaotic and unpredictable monarch who brought storms and drought and the people turned on each other in their efforts to survive.
Set was also the archenemy of Horus. Many tales speak of the battle for control of the world between Horus, son of Osiris, and his uncle Set. The manuscript is the story of the legal battle before the gods over who is the rightful king of Egypt. Horus and Set both present their cases and then must prove themselves in a series of contests and battles which are all won by Horus who, in the end, is proclaimed king.