Lethe

Lethe is one of the Thirteen Planes, it is aligned with Luna and is the realm of the dead. Once a soul arrives in Lethe it is destroyed forever, thus the conditions of ones entry are strict. Only once a soul has been rejected or slain from the immortal planes (Vidsfar, Altum, and Mirov-At) does a soul enter Lethe where it over time decays into nothingness. Just as Sol exists only in a physical form in Vidsfar, Luna takes their physical form in Lethe, and takes the role of a grim reaper, ushering souls through their destruction.

History
Before the creation of the mortal realms and modern deity's there was a void containing nothing, but the existences of two beings, Sol and Luna. Together they created Pragma, bringing matter into existence, and beginning time. This creation began to eliminate the void however Luna saved a pocket of nothingness as their respite, and home for their physical being.

Popular Opinion
Lethe is seen in mainstream religion as the worst of all possible outcomes and those whom submit themselves to it are cowards, and godless. The worship of it is banned by many priests and frowned upon in all societies. However there are known cults who do plan on going there after death through ritual sacrifice. One of the major organizations who revere this plane is an assansins guild known as Umbra Lamina. Members of this guild perform killings that assure the soul enter Lethe before journeying through any other of the immortal planes with the assistance of Svampen.