The Throne of Death

To many scholars it seems curious that gods of Death should die. Perhaps the force they govern is so relentless that ultimately it consumes even them, proving that nothing can escape fate.
The earliest recorded god of death was referred to as Nerull. He was worshiped in fear by the peoples of the Inner Sea for thousands of years. Nerull was seen as mad and sadistic, depicted in the classic image of an aged man, half skeletal in a black robe and wielding a scythe. Mourners prayed that their dead might avoid his gaze and pass safely through Death to their ultimate fate.
Within his mythology lurks a pair of shadowy figures thought to be his consorts. Their origins cannot be certain, nor their relationship to one another. The child of another god stolen away? Mortal souls he fancied? One story tells of an Elvish queen who who took her folk into Death to avoid a cataclysm. They appear in iconography from ages past standing behind Nerull - one seated at a loom spinning the fates of mortals until Nerull took them, and the other seeing to the deaths of beasts and plants, ushering in winter accompanied by her ravens.
As civilization reemerged from the Age of Darkness, the worship of Nerull did not return with it. Instead, the Spinner and the Lady of Winter took possession of his domain, with Phrasma, Lady of Fate, taking the Throne of Death and the Raven Queen governing the natural cycle of life and death, ensuring that souls reached Pharasma for judgement and disposition. These goddesses were not feared as Nerull had been, and were not seen as twisted and evil, but rather as impartial and necessary, though both were rightly feared by necromancers and intelligent undead.
Near the end of the Age of Lost Omens, a War for Death took place, with the reborn Hakotep, the Forgotten Pharaoh traveling into death and sacking Pharasma's mausoleum, slaying the goddess and breaking Death itself. This led to the terrible global event know to us now as The Rising. The war ended with the destruction of Hakotep some years later, leaving the Raven Queen to assume the Throne of Death, consolidating its power to herself once again.

Appendix A: "Death and its rulers" from Two Lives of Hakotep I by Nouf Serethet

Current Ruler of Death The Raven Queen, goddess of death, fate, and winter.