The Gloaming

The Gloaming are a collection of dark fey that have moved from the fey wilds of Arborea to the shadowy lands of the Underneath. They pledged their service to the Raven Queen much like other fey serve the court of Queen Mab.

Shadar-Kai

Shadar-kai, also known as shadow fey, are a race of shadow-like fey connected to the Underneath. They are believed to have originated as an offshoot of eladrin associated with the Raven Queen, although other legends of their origins also exist.
Some shadar-kai resemble blighted elves, in a perpetual state between life and death, while others are human-like in appearance. They are usually slender and range from slightly taller to slightly shorter than humans, exhibiting graceful movements well suited to stealth.
They have dusky gray skin and colorless complexions that vary from alabaster to dark gray; black hair, with few shadar-kai having pale hair, that range within human hair colors; and dark eyes lacking any sclera or clear pupil. Shadows on their bodies or clothing always seemed to be deeper and darker than shadows elsewhere, and shadow seem to follow them and reach out, especially when they are angry. They are easily lost from view. Many shadar-kai display all kinds of iron body piercings in nose, ears, eyebrows, shoulders, and other parts of the body, and purple-inked tattoos on body, limbs, and face.
Despite having a somewhat youthful appearance while in Andorra, being in the Shadowfell reveal the shadar-kai's cursed state. They appear visibly aged and withered, with swollen joints that gave them an overall corpse-like aspect. For that reason, many shadar-kai wear masks to conceal their decrepit state while in the Shadowfell.

Hags

Hags are horrible witches of wicked intent and ancient origin, dark fey tied to primal forces whose foul magic and mysterious malevolence haunt fairy tales and nightmares. Equal parts hideous and heinous, hags embody what it meant to be ugly inside and out, taking on the forms of unsightly old women. They are the antithesis of Feywild natives like the eladrin, for they are warped reflections of civilized beings that epitomized nature at its most repugnant
Hags are almost universally unique in their exact forms and mannerisms, but there are typically common physical traits between them. Generally, hags look like crooked crones, wrinkled and withered women of unsightly appearance with blotchy skin marred by warts and moles. Their long, skinny fingers are tipped by talon-like nails as tough as steel and as sharp as blades, and their mouths are filled with sharp, blackened teeth and noxious breath. Long, frayed hair ringed their creased faces, but even though their faces were heavy from their malice, the glimmer of sly villainy could still be seen in their eyes.
Normally hags wear simple clothing like those of female peasants, if more ragged and dirty, but not for a lack of interest in their appearance. In fact, hags were very concerned with their appearance, taking steps to ensure they are at their worst by rubbing filth onto their clothes and accessorizing their gross garb with gruesome decorations. They will modify their clothes with bits of gore and refuse, wear bits of skin and bone, spin cloth from innards and put all manner of litter in their hair, and those are only the things they will wear. They are also known to augment their actual bodies, such as by sharpening their teeth to make themselves more fearsome, picking at scabs to produce weeping sores, and otherwise exacerbating their deformities with nurturing attentiveness.
However, if a hag needs to not invoke utter disgust, they can magically disguise themselves, the exact limits of their illusions being specific to different types. Almost all types can take on the forms of regular old ladies, but some can appear to be attractive youths, diminutive giants and even vaguely humanoid animals like bears. Regardless of what guise they don or act they put on however, such impersonation would always be superficial, because the physical forms of all hags are merely reflections, the twisted moldings of the ugliness in their own hearts.

Bone Fairy

A dark fey that has a constant hunger for bones, but will settle for teeth as well. Bone Fairies are the mothers of tooth fairies, like a queen bee is the mother of the hive, and she is able to communicate to her "workers" through telepathic means. She appears like a twisted elf or eladrin, with greyed skin and pitch black eyes. She has no lips and instead her jaw is an exaggerated feral grin of fangs. Bone Fairies that end up on Andorra tend to set up in the wilds around settlements, sending in their tooth fairies to steal the townsfolk teeth during the dead of night. Sometimes she will attempt to ensare wanderers to her lair so she can feast on the bones she prefers, and sometimes she is even willing to make deals with less than moral visitors. A bone fairy is not against trading boons or treasures for a feast.

Tooth Fairy

A small, winged dark fey creature notorious for stealing the teeth of sleeping country folk. They resemble small winged goblins with insect wings and a grey hue. All tooth fairies serve a hive queen called a bone fairy. It is known that you can reverse the damage of a tooth fairy infestation by dealing with the tooth fairies themselves. Because teeth are taken from Andorrans through magical means, finding the stolen teeth can allow a cleric to reverse the damage done. Teeth and bones are the primary diet of these dark fey, so sometimes there is nothing left to rescue. This is rarer though, as both tooth fairies and bone fairies tend to horde such items.

Baba Yaga

Baba Yaga is an extraordinarily powerful mageand archfey. Some describe her as the most powerful female mage ever known, a sorceress with a reputation for passing throughout the planes. In doing so, her magical hut also appeared elsewhere, and is reported to have been seen on Andorra. The normal position of Baba Yaga's hut when it has not traveled is in the forested wilds of the Underneath.
The 5‑foot-tall (1.5‑meter) sorceress is said to be of godlike intelligence, but very physically ugly. She has a long warty nose, a skeletal frame, and thin white hair. She has sharp, iron-like teeth and fingers that curve into claws. On occasion she has a rather plump frame. It is uncertain whether her changing frame is due to having recently eaten or simply on a whim of preference.
She is known to have a fickle nature, being dangerously unpredictable, equally as likely to eat her worshipers as she was to aid them. Politeness will not guarantee her favor, nor will rudeness ensure incurring her wrath.
She is willing to offer people some of her secrets in return for another. The bargains she offers people were also far more dangerously worded than those of any fey. Baba Yaga, being a powerful arch fey, is available as a patron for warlocks.