The Clay People are a tribe native to the planet Mars who inhabit the region known as the Valley of Desolation. The Valley of Desolation contains a network of caves and underground tunnels in which the Clay People live. Like the walls of these tunnels, the Clay People largely consist of clay and have the ability to melt or blend into these walls, and possibly actually pass right through them. However, the Clay People seem dependent upon this environment for survival and cannot leave. They have a simple social structure with a single ruler, the Clay King.