The path of the Descent as illustrated by Aitrus, highlighted in green.
The Descent is the name the DRC use for the path connecting Earth's surface to D'ni. Among modern-day explorers in D'ni, "the Descent" is often a term specifically associated with the Great Shaft, but it encompasses much more than that. Its full extent spans from the volcano in Eddy County, New Mexico to the D'ni cavern. It stretches down over three miles, passing through the Great Shaft, a natural cave system, a magma chamber, and the Southern Gate—the outer-most extent of the D'ni empire.
This path was constructed by the D'ni between 9336 and 9337 DE. It was excavated by a small team from the Guild of Surveyors, including Aitrus. They were tasked with digging a tunnel to the surface that could be walked with minimal difficulty—and which could be easily defended from invaders, should humans have proved to be hostile. It was constrained to a maximum incline of roughly 22 degrees, and excavation ran for over a year before impatience within the Guild Council prompted the construction of the Great Shaft to complete the route quickly with a direct, vertical ascent.
There are two entrances to the Descent from the surface. One is from within the caldera of the volcano, while the other—the "Ti'ana/Loftin Entrance"—is elsewhere in the New Mexico desert. Both entrances connect to the top of the Great Shaft, but only the Ti'ana/Loftin Entrance is used and controlled by the DRC. The volcano entrance is on property owned by Jeff Zandi, whose father was one of the co-discoverers of D'ni in the mid-1980s CE. Explorers do not have direct access to either entrance, however. For them, access to D'ni is obtained through Relto, an Age provided by Yeesha as part of the first Journey.