A subterranean variant of the Sphexxian race, Cavern Sphexx are immediately recognizable due to their almost colorless bodies, a product of the very limited exposure to light that they see in the underground tunnels they call home.

A life spent in near complete darkness has given the Cavern Sphexx abilities that are expertly suited for work in the deep mining colonies spread across Cosmerrium. These subterranean Sphexx come in two varieties, the sixarmed "Tunnelers" which conduct drilling and excavation operations, and the rarer winged "Fliers", which are tasked with running messages and supplies from the surface of the mines to the deep, dark tunnels below.