Lunes

One of my own ideas, and only exists in Worlds of the Fey.

Lunes are Fey like, though they prefer to live underground and sleep during the day.
Lunes are no taller than 5 feet, their bodies tend to be on the slimmer side. Their whole body is comprised of thin black fur, and their yellow eyes have been known to scare especially since they glow in the dark a bit. There are extremely rare white furred Lunes.

Lunes are seen as forest guides, they help others find their way home. It is very proper to give head pats and thanks upon being brought to the right path. They do accept food as well, mainly fruit.

Unfortunately, there are those that hunt and kill Lunes for their fur, as it helps thieves sneak in the night. The fur does tend to soak up light, and allows one to blend into the shadows as if said person was a shadow.

Lunes do their best to help a lost Mortal home.
If one does not have a home, and if one is good enough. A Lune may bring back the mortal in question.

Under ground where light is hard to reach, they build upon pillars or make natural looking pillars that reach up to the cavern ceiling. They build their castle atop these pillars. The stone they use helps absorb light to keep it hidden from wondering Humans but to also keep hidden from monsters. To keep monsters out, they enlist the aid of Fire Nymphs to bring them lava to run down the pillars that hold their castle up. It is not uncommon for at least one Fire Nymph to live with a colony of Lunes. This way the Fire Nymph can circulate the lave from the bottom of the cave, back up to the castle, in an endless lavafall, that is if Lava is needed in the first place.

Now one would think that a Lune Colony would be easy to find due to the light from the lava, but that is where not only the stone they use comes into play, but how they build the structure, to make it look very much like a natural part of the cavern itself.