Dolurrh

Dolurrh, the Realm of the Dead, is the ultimate resting place of most mortal souls. It is not a reward, or a punishment, it simply is. Souls that make it to Dolurrh are overcome with apathy, gradually forgetting who they are until they eventually fade away entirely. Dolurrh does not embody the concepts of death, or dying, both of which fall under the portfolio of Mabar, instead it simply serves as the final resting place for the dead.
When a mortal dies, their soul is pulled to Dolurrh within moments of their death, and their memories begin to fade as soon as they reach the plane. It doesn't take long for most spirits to fade away, a matter of weeks. Dolurrh's role as the resting place of the dead is well known throughout Eberron, and every religion has their own beliefs about what happens to a soul after it has faded away. The Undying Court and the Blood of Vol believe that existence ends in Dolurrh, that there is nothing beyond it and a soul that has faded simply ceases to be. The Sovereign Host asserts that Dolurrh is the gateway to the realm of the Sovereigns, and that a soul ascends to this realm after they fade from Dolurrh, and the Church of the Silver Flame believes that noble souls join with and strengthen the Flame. What remains in Dolurrh is but a husk, the cast off remnants of a soul, like the shed skin of a snake. Regardless of their beliefs, everyone agrees that once a soul has faded from Dolurrh, it never returns.
Dolurrh is theorised to be the 13th plane. It has no thematic opposite like the others, and it seems to serve a purpose more than it embodies a concept. It doesn't judge the actions of the mortals who end up there, that responsibility lies with Daanvi. Dolurrh is simply the end of the road. Dolurrh is gloomy, colours and sounds seem muted and washed out, the vibrancy and joy sucked out of everything. The whole plane appears to be underground, and no one has ever seen the sky in Dolurrh.
A heavy feeling of ennui settles over any creature that travels to Dolurrh, sapping the motivation to do anything other than sit down and fade away. This ennui seems to impact more than just the creatures that travel to Dolurrh. Magic and spellcasting seem to be impeded in Dolurrh, and it takes significantly more effort to cast a spell than it would elsewhere. The longer a creature stays in Dolurrh, the worse the ennui gets, until eventually they do as the dead do, and simply stop.

Type

Dimensional plane