Shu is the twin of Tefnut and offspring of Ra's primordial creation. Shu means "to raise," implying his role in the universe. It is Shu's job to hold up the heavens, thus becoming the god of atmosphere. He is depicted as a human holding up his daughter, Nut. He is the barrier between sky (Nut) and earth (Geb), the union of which he opposed. Shu succeeded Ra in becoming ruler, but like Ra, experienced disorder and dissention, in particular, on behalf of the evil serpent, Apep. Shu finally abdicated his throne and gave it over to Geb.