Night hag

Night hags are incredibly evil creatures hailing from the fiendish planes.

They are known for their mercilessness and ability to walk in the dreams of others. In the fiendish planes they are popular creatures, being the creators of the process that creates altraloths but much more notably for being able to harvest soul larvae which are used as currency in the Abyss, Blood Rift and Nine Hells. They also have an affinity for nightmares.

Description
A night hag is always neutral evil. A night hag has an array of magical powers, and can transmit a disease called "demon fever" by biting a victim. Night hags are also able to torment chaotic or evil individuals by invading their dreams using a special item called a "heartstone." This process eventually transforms the victim into a larva unless some force capable of affecting ethereal beings puts a stop to it.

Night hags are believed to have created the altralothss, powerful unique yugoloths.

Night hags, being exclusively female, can only reproduce by mating with a male member of another species, typically a member of a civilized race. The hag often slays her mate. The child born looks like a normal member of her species with black or blue hair and is often given into foster care by the hag disguised as a normal woman. When the young girl reaches puberty, the mother hight hag might visit the child several times and, after several rituals, transforms her offspring into another hag. Interrupting one of the thirteen rituals that takes place ceases the process of transformation.

For reasons unknown, some night hags give birth to accursed offspring known as dusk hags.

Cegilune is the goddess of the night hags, or possibly just the most powerful one of their kind who has since gained a shred of divinity.