Deep Ways

Place

The Deep Ways are hidden paths through the One Mountain that connect many other places throughout the multiverse. Here's a relevant excerpt from a Dvaren text:

As with all underground realms, the Deep Ways are treacherous and merciless. They are ever-changing through seismic and volcanic activity. These challenges didn't stop the Dvar. The Mordinsamman Church teaches that the Deep Ways are how our people found our way to other worlds, through courage and perseverance. In most cases, the Deep Ways back to Dvarholm were lost, often due to the constant movement of the multiverse, expressed in One Mountain as earthquakes and magma flows. In many cases, the fact of Dvarholm has become a matter of myth or faith. Nevertheless, the Covenant of Moradin offers all Dvar the way home, earned by the choices they make in life.

The Deep Ways aren't the Underdark. On most worlds, anyone can reach the Underdark if they simply go deep enough. The Deep Ways are transplanar connections. They're reached not through downward movement but lateral. There's an art to finding them that transcends spelunking or mining.

((Part of my inspiration for the Deep Ways are the many "backstage" areas in our world, like the hidden corridors and tunnels of shopping malls and amusement parks. Like the Feywild and the Shadowfell, the One Mountain is a "backstage" part of Prime worlds.))