Imps are in essence the "working-class" of Hell's society. They have the lowest ranking in Hell's hierarchy and therefore are the least respected and most likely to be hired for slave work or as servants. There is a hotspot in Hell for imps called Imp City, which appears extremely shabby and filled with homelessness even by Hell's standards.
- Blitzo's family
- Millie's family
- Wally Wackford
Imps are designed to look like how the devil is typically portrayed in media, with horns and an arrow-shaped tail. All Imps share the same color of skin and striped horns; their color schemes simply consist of primarily red skin, with additions of details, markings, stripes and blotches in black and white providing strong contrasts. Their eyes have prominent yellow scleras that glow in the dark, black slit pupils, and sometimes visible red irises.
Imps come in a variety of shapes and sizes, although the most common ones appear to be around the same height as an average human adult, but with many of them being significantly shorter. One of the most distinctive traits that tell them apart is the shape of their horns, which can vary greatly from individual to individual. As first shown in "Murder Family", Imp blood is usually black. Imps exhibit sexual dimorphism of their hair and horns: female imps have mostly dark hair and black horns with thin white stripes on them while male Imps have mostly white hair with striped black and white horns. Although these are predominant traits, there are apparent exceptions, such as a male Imp with dark hair that can be seen in the backgrounds of the episode "Loo Loo Land" and Striker in "The Harvest Moon Festival"; while he had white hair, he also had a black mustache. In Blitzo and his sister, Barbie Wire's, case, they would be considered bald.[note 1]
Imp heads are relatively large compared to their bodies, and have some vaguely reptilian traits, such a lack of ears, lack of defined noses, and their heads often have a slight conical pointiness towards the upper lip. Imp head shape varies notably, such as Blitzo and Barbie Wire having elongated rear craniums. Although they usually appear to lack any nostrils at all, giving the middle of their face a bare, alien look, though they are revealed to actually have nostrils when actively smelling something. Their teeth are usually shown as sharp and conical, and their tongues are forked like those of snakes.
Imps arms and legs have some amount of variation, they may have either plantigrade or digigrade feet, often with hooves or claws, which are usually black. Blitzo is even shown to have natural high heels on his feet. Both Blitzo and Barbie Wire have wrists and ankles which are relatively thick and undefined.
- Ocular illumination: Imps have the ability to project light from their eyes when they are in dimly lit areas.
- Pyrokinesis: At least some imps are capable of producing flames, such as the Imp carnie in "Loo Loo Land", who lights a cigarette made from a bill with a flick of his finger.
- Fire resistance: As shown in "Murder Family", Imps are immune to fire and being fully engulfed in flames does not harm them. It is unknown if this is an ability unique to imps or if it is a trait all demons possess.
- Flight: Some, but not all, Imps are born with wings behind their backs, which grants them the ability to fly.
- Unique abilities: Although more of it has yet to be shown, some Imps appear to have traits that is unique to individual Imps. An example of this is their ability to make unique animalistic sounds, with Blitzo generating cat-like purring and Striker's tendency to hiss and rattle his tail.
Unlike sinners and humans, it appears in the episode "Loo Loo Land" that Imps can be killed by non-Exorcist weapons. For unknown reasons, either due to being members of the lowest class of demons or some other cause, it is implied that Imps can suffer from lethal traumas that goes from knives to guns and even being petrified into stone from Stolas's gaze. A headshot from a gun would also be significant enough to kill an Imp completely.
In the episode "The Harvest Moon Festival", it is confirmed by Millie's parents that Imps can die as one of their farm hands perished in a fire tornado. It is also further clarified that participants in the Pain Games (which are mostly played by Imps) suffer several deaths, some implied to be committed by Millie herself. Additionally, Millie's sister Sallie May is confirmed to kill quite a bit.
- In European mythology, an imp is a minor type of fairy or demon that is typically more mischievous than threatening, and as such is deemed a lesser being, even servile, to supernatural entities.
- In the episode "Murder Family", Blitzo is injured by a bullet while in the human world and later implies that a shot to the head would send them back to Hell. This statement may be true based on Millie's reaction, but is never outright confirmed or denied on-screen.
- It is possible that young Imps are called "Implings", as Robo Fizz addresses them as such in his show.
- Some Imps are revealed to be able to have wings.
- According to Striker, Imps don't typically start businesses on their own due to how low they are in Hell's hierarchy.
- As hinted in Stolas's greeting before he starts the ritual for The Harvest Moon Festival, majority of Imp-kind appear to be native to the Wrath Ring.