Shu was the god of the dry wind, air and atmosphere. According to the Heliopolitan creation myth Atum created She and Tefnut as the first couple. In their turn they creat Geb and Nut.
The god She is often shown on 21st Dynasty coffins separating Geb and Nut. However, unusually on our coffin, Heka takes this role.
He is often shown with his hands raised to hold up the sky goddess. The sun disc is shown to represent the sky.