Set carried a great weight in the dualistic world view of the Ancient Egyptians. He was all that was chaos, destructive, or even foreign. And yet his powers were needed to create balance. While over time he accrued more and more the reputation of a god of evil, his was the duty to protect the barque of Re, spearing the Apep (Apophis) serpent as it threatened to swallow the sun-god every night. As Lord of the Desert, the red god, he was opposed to his brother Wesir, whom one myth has him slaying and later dismembering. Set represented the raging sea, while Wesir was equated with the life giving Nile. He was also the Netjer (god) of storms. He was also considered brother to Heru (Horus), who he also fought for the throne of Egypt, losing a testicle while Heru lost an eye. It was Set who was defeated even though he was supported by Re as the elder. He remained a companion of Re in his protective aspect against Apep and could be called upon to hold his storms and create good weather.

As part of the Heliopolitian Ennead he was son of Newet (Nut) and Geb. It was described in at least one text that he ripped himself from the body of his mother. His main cult center was Nubt in the 4th Nome of Upper Egypt where he was venerated and respected. He was represented in human form with the head of the Set animal - a beast shrouded in antiquity. The Set animal had a curving muzzle, erect square tipped ears and erect tall. Various interpretations have been given of the animal, suggesting an aardvark or anteater, or that it originally was an ass - one of the animals associated with Set, along with the pig, antelope, crocodile, fish, and the hippotamus. Many authorities believe the Set animal is a composite or symbolic animal with no natural counterpart. His consort or wife was his sister, Nebt-Het (Nephthys), and he was also mated with the foreign goddesses, Astarte and Anat.