Shadow Imp
Not all creatures of shadow magic are deadly to people. Shadow imps are one such example. The size of a child, they are known for being mischievous and causing chaos wherever they go. In cities they make artisans' tool go missing or steal products from merchants. Outside the cities they prey on farms. Their favourite is to steal eggs from hens.
Hey, imp! Get back here!
Appearance
Shadow imps are humanoid in appearance. They walk on two legs and have two hands free to manipulate objects. Their ears have, however, more in common with elves than with humans with its pointy shape.
They appear very skinny like they had almost no muscles under their dark grey skin. Imps also have very little hair on their heads and what they have is so white that it is almost invisible.
Habitat
Shadow imps live in almost every area of the world. They can be found in the Shadow Forest, the Shadow Realm and many other places. They like spending time close to people as it gives them oppurtinities to be mischievous and play tricks. Their tricks often result in humans being annoyed and angry. Many merchants employ special guards who are on a lookout for shadow imps.
Origin
The same as shadow monsters of the Shadow Forest, shadow ghosts and shadow sea monsters shadow imps are the creation of shadow magic. However, unlike the other types of shadow creatures their physical form seems to be solid and not ethereal. Additionally, they are much less violent than others. Proposers of the theory that shadow magic killed the elves don't have any concrete explanation for why a mischievous creature was created for that purpose.
In my opinion, shadow imps served as saboteurs and skirmishers in the shadow forces which destroyed the elves. They sowed confusion and chaos among the elves.
Definitely mischievous, although I would expect them to be more active at twilight or nighttime than during the day, which the merchant quote seems to imply (this is possibly a personal bias in my reading though) If they are truly immortal, as opposed to just ageless, you may want to add a bit about durability or the ability to turn insubstantial at will to avoid being harmed by the special guards hired to look for them, as I imagine they are not usually treated with anything approaching kindness by the other denizens of the world.
Thank you. I think that the ageless option (immortal, but can be killed) is the better option
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