Acheri

Acheri is a type of demon that can materialize their own form without the need of the use of a vessel, generally, if not always, taking the form of little girls.

In All Hell Breaks Loose - Part 1, Ava Wilson summoned and controlled a demon, called Acheri, with her powers, using it to kill both Lily and Andrew.

Appearance
Acheri can take the form of a little girl without the need to form a vessel. However, they hide the second form with features that any typical human would call monstrous.

Known Abilities

 * Body Materialization - Unlike all other demons in the show besides Daeva and Hellhounds, the Acheri is the only type of demon that can take human form without possessing a human body.
 * Shapeshifting - They take the shape of little girls so that people trust them. The demon can reveal its true form when it is about kill its prey. It's possible that the Acheri's true face is how the true faces of all demons appear.
 * Super strength - Like all demons, Acheri are physically stronger than humans and can rip them apart.
 * Invisibility - Acheri can become invisible so they can play tricks on humans before killing them.
 * Super speed - Acheri are supernaturally faster than humans.

Weaknesses

 * Salt - They aren't able to cross or touch a line of salt.
 * Iron - Like most Demons they can't touch iron.
 * Demon-killing Knife - It can can every type of Demon except knights of hell so it most likely kill an Achero

Mythology
In Native American mythology, an Acheri is the ghost, or spirit, of a little girl who comes down from mountains and hilltops at night to bring sickness to humans, particularly children. The only defense against an Acheri was thought to be a red ribbon tied around one's neck.