After Death

Before the Curse, with the exception of very rare cases of divine necromancy, the souls of mortals were all either reincarnated or went to the Afterlife after death, depending on species.
The Curse affected this in several ways. Firstly, it greatly increased the prevalence of undead. In addition to giving far more people the power to raise undead, it also confused the pathways for souls to move on, and many souls now get lost, becoming ghosts or similar beings. This is especially likely in places where a lot of people have been practicing arcane necromancy.
Secondly, the death of Atis and Iangolor's attempt to take his place shattered the Afterlife, and many souls don't really have a place to go. The elven afterlife was utterly destroyed, shunting all the souls in it back to the Material Plane. Most joined the recently-dying elves in falling back into the ancient eladrin pattern of reincarnation, while a few became banshees.
Lastly, several individuals took initiative to fill the gap to their advantage. Both factions in the Abyss developed the ability to capture lost souls whose personalities were similar in nature to their own, drawing them into the Abyss to use as fuel or convert into new devils and demons. The hags joined in this industry, since night hag stole the secret from the soulstealers of the Abyss. Not to be outdone, several entities in the Celestial Realms figured out how to do the same, creating an industry around trying to collect and use souls.
Soon, they did not limit themselves merely to capturing already-wandering souls, but turned their attention to the living. The night hags developed a cruel and unique method of corrupting a person's soul through their dreams, allowing the night hag to slowly kill them and trap their soul in her soul bag. Many other entities used more gentle methods, encouraging the living to pledge themselves to them and marking their souls with consent in order to lay claim on that person's soul whenever they eventually do pass on.

Type

Metaphysical, Astral