The Cosmological Consequences of Death and Dying

Since Uthilith follows the cosmology of the Great Wheel, dying while in worship or service to one of any deity will result in either a) an afterlife in that plane if you held the tenants of this particular deity or b) judgement by said deity should you have failed to uphold that doctrine during your life. Though few and far between, nonbelievers who reject the existence of the Uthilithian pantheon despite physical proof of their existence will be judged to their afterlife accordingly by Lation, the god of fate.
Before being sent to the outer plane of your afterlife, you’re greeted by Vanth - a winged celestial (though not a goddess) of unsettling presence. She watches over the Liminal Plane, an area between even that of the Astral Sea and other cosmological bodies, to ensure that none linger for too long. Thus, she provides a limit on the time a mortal soul can spend within this point of ferry - ten days. If the soul is either resurrected by Revivify, Reincarnate, or Raise Dead during this period, Vanth allows the soul to run free without much issue (merely calling for a sum of coin, doable for any adventurer). If the soul lingers after the maximum allotted time, Vanth shifts them away to their plane of worship or judgement without further thought. Thus, material components are significantly more expensive in Resurrection, True Resurrection, or Mass Resurrection - the more gatherings of souls Vanth has to perform, the more burdensome it is for her.

Deity Residence:

• Lation - any law-aligned plane, with the exception of evil (resides in Elysium)
• Enaldir - Mechanus, Arcadia, Acheron (resides in Acheron)
• Phaedron - any elemental plane, Pandemonium, Limbo (resides in Limbo)
• Briris - any good-aligned plane (resides in Bytopia)
• Achlýs - any evil-aligned plane (resides in the Abyss)
• Uvta - any law-aligned plane (resides in Arcadia)
• Ciden - if the worshipper focuses on a particular denomination to Ciden, then they’ll end up in that plane (detailed later). However, if Ciden is the focus of their worship, they’ll end up in the Beastlands.
• Dydos - any chaos-aligned plane (resides in Pandemonium)
• Platonius - worshippers of Platonius are another exception to the rule of judgement. Lation judges all who follow the love god, as their motivations are significantly less monolithic than a lot of others in the pantheon.
• Sibyll - Arcadia, Mechanus, Mount Celestia (resides in Mount Celestia)
• Zisnera - Elysium
• Brunhilde - Mechanus, Acheron (resides in Mechanus)
• Avandra - Beastlands, Arborea, Ysgard (resides in Arborea)
• Lolth - any evil-aligned plane (splits time between the Nine Hells and the Underdark underneath the Secondary Material Plane)
• O'sha - any law-aligned plane (resides in Mechanus)
• Gruumsh - any chaos-aligned plane, with the exception of good (resides in Pandemonium)
• Verna - Elysium, Beastlands, Arborea (resides in the Beastlands)
• Notus - Arborea, Ysgard, Limbo (resides in Limbo)
• Melancholia - Bytopia, Mount Celestia, Arcadia (resides in Mount Celestia)
• Polaris - Acheron, Gehenna, Gray Wastes (resides in Acheron)
• Agape - any law-aligned plane (resides in Arcadia)
• Eros - any chaos-aligned plane (resides in Ysgard)

Changes to the RAW 5e death system:

Every time a resurrection spell is used, the caster of said spell is required to make a check using their spellcasting stat with no proficiency bonus added. The first death is a DC of 10, with the DC increasing by 1 for each subsequent death. If the DC is not met, however, the character is dead (not permanently, but another resurrection spell can't be cast by the same caster for 24 hours if they fail) and the material components for the resurrection spell are wasted. If a natural 1 is rolled on the check, the character is permanently dead - nothing short of a Wish or True Resurrection can bring them back to the world of the living. If the check is failed and the character's death DC has reached 14 (ergo, 5 total deaths), then the character is permanently dead and can only be brought back with a Wish or True Resurrection.
If the spell being used is one of fifth level or higher, a ritual skill challenge can be used to lower the spell DC. Three other individuals must contribute to the ritual in order to successfully lower the DC - each individual must create a way to bring the deceased back through things they've learned on their journeys. With a satisfactory religion check, you may be able to implore Vanth or the deceased's deity to assist in bringing them back to life. With a high intimidation check, you may even be able to frighten the spirit of the deceased into returning to their body. However, two of the same check will result in the second being a significantly higher DC to assisting with the ritual - the resurrection traditionally counts on all three individuals utilizing their own skills to bring the deceased back from the Liminal Plane.