Lyesh

Lyesh is the intermediate plane of death in Arkannan cosmology, serving as a place for the souls of the dead who didn't have a deity in life to wait, sometimes for eternity.

The Island
Lyesh takes the form of an island. It has no plant life, as barren, rocky soil covers the ground. The island is permanently covered in a dense, gray fog, and little can penetrate it. Upon arrival, the rare living visitor will note that, at some point, this island was inhabited. There's three small huts near the dock, and artifacts of their previous residents' lives can still be found. In the middle of the island, bisecting it, are three lakes. The lake in the middle has opaque gray water, to the left is a black lake, with oil-like water, and to the right of the gray island is a white lake. Each lake has different effects, but those are detailed later. There's also a large, 100-foot deep pit that houses many of the island's oldest forgotten spirits. On the farthest end of the island are ruins of a former stone circle.

The Lakes
The white lake contains water from the Plane of Elysium, shunted to the island at the time of its creation. When ingested, the water restores and heals, returning the drinker to their best state.

The gray lake contains water from the Outlands, and serves as the balancing force for the island. Drinking the water changes the drinker's alignment to true neutral.

The black lake contains water from Hades, sent to keep the island grounded as, primarily, a temporary land of the dead. Drinking the water causes the bearer an incredible amount of psychic damage and can potentially strip the drinker of their personal memories.

The lakes serve as the island's sustenance, what it needs to continue existing outside of the planes. Should the lakes be drained, Lyesh would cease to exist, and if some of the lakes are drained, the island's alignment would shift, causing a whole host of other problems.

Mythos
The general population of Lyesh are deceased humans, given that humans are raised generally without religion, and pick deities upon reaching adulthood. When someone is content without picking a deity, or they die before they choose, their souls are sent to Lyesh. Once their souls reach the island, they are claimed by the deity that the soul most closely followed in life, however unknowingly.

Since the death process is scary, one unclaimed soul named Constance has made it her life's (or death's, I guess) mission to guide souls to the island and to their afterlife. It's unclear why Constance was never chosen by a deity, although some believe she declined her deity's offer and chose to stay on the island to shepherd the souls that come to Lyesh.