Demons

This species of unknown name, being called Demons by the children, Man-Eaters by the unnamed man, Monsters by the Goldy Pond Resistance and simply as They by Sister Krone, are tall humanoids with monstrous appearance and the main antagonists of the series. They are the beings that command the "Demon World" in Factory Farming and Premium Farms.

History
It is currently unknown how the "demons" got to Earth or if they were native to Earth at all. Anything after the year 2015, which is stated by Ray to be the last year of any updated book at the Grace Field House.

According to Sung-Joo, "Demons" preyed on Humans in times of old, until some of the Humans started to fight back. After countless deaths and wars, a promise was formed between the "demons" and the Latley family. The human and demon realms were split in two, where neither was allowed to cross nor hunt each other. The Latley family left an unknown amount of humans in the demon realm, stranded with no way to escape, to become livestock to the demons in order to keep peace in the human world. Thus the plantation system was formed via a loophole, as the demons were not hunting them.

Appearances
All 4 known varieties of demons bear different and unique appearances to distinguish from one another.

Farm Demons
Farm Demons are all tall beings that have a long pointy face with two eyes above each other and two horns on top. They have a mouth with sharp canines and a long tongue. They have long arms, six fingers, and sharp nails. They each have four limbs and walk on two legs.

Some demons have been seen with a pipe connected to their face. It is currently unknown what this is for. All demons so far have also been seen wearing a black cape.

Heathens
Heathens appeared to have the most human-like looks compare to the other varieties of demons— they each have four limbs and walk on two legs. Sonju, a heathen, unlike the other heathens and demons, is shown to have one horn instead of two located at the top of his forehead.

Just like the demons, the heathens are polydactyly, with six fingers on each hand and wear masks which allow them to see through two holes positioned at the top and bottom.

Poachers
Poachers appear to be the wealthiest kind of Demons around. They look and behave the same as Heathens but are well-dressed and act politely. These demons also wear masks to protects their eye from any harm. Poachers appear to have 3 long fingers on each hand, have tall slender bodies and quick reflexes. They also seem to be really fast, showing this with their exceptional abilities and skills.

With the death of Lewis, all known Poachers are deceased as of now.

Wild Man-Eaters
Being the least human-like than their other counterparts, man-eaters crawl on six legs and have numerous eyes, and are completely unclothed. They also appear to be the largest of the species. They also don't have the ability to talk. The Man-Eaters also have the same weak spot as all the other demons: the eye in the middle of their skull.

Powers and Abilities
The powers and abilities of demons vary. For anthropomorphic demons, similar to humans, they can walk on two legs and speak human language. They also communicate with their own kind with their native language. Several anthropomorphic demons are often seen equipped with weapons such as spears and daggers, which they use to hunt humans and even their own kind.

Whereas for wild demons, also known as man-eaters, move on four legs. These type of demons are known to hunt in packs and one can let out an ear-piercing scream to signal to its surrounding allies. Wild demons are known to be physically adept (and possibly more so than their civilized counterpart) as shown as they are capable of running, pouncing onto their prey, and climb up trees at great speed. Wild demons are also shown to be rather invulnerable to human attacks unless they are aimed at their eyes, which is considered their weak spot.

Regeneration: Demons can heal any kind of (their) wounds, except their eye.

Demon Eating: Can be eaten by other Demons. Nous at Nouma.

Weaknesses
Middle Eye: Currently, there is only one known weakness the demons have: Their middle eye. Figured out by Ray, anthropomorphic demons are always seen wearing masks which either partially or entirely cover up their faces (with two holes on the top and bottom which allow them to see)- they are used to protect the eye right in the middle, as it is known to be a demon's most vulnerable weak spot. Once the eye is destroyed, the demon would immediately die.

Heathens
The Heathens are specifically known for their religious beliefs of not eating humans. They also have the most human-like appearance compare to the rest of their kind.

Man-eaters
Unlike their other counterparts, man-eaters are wild and more aggressive, who live in packs. They also crawl on 6 legs. Man-eaters appear to behave like animals instead of Human-like Demons.

Poachers
The Poachers appear to be some kind of high-class Demons who are well dressed and live in wealth, unlike the Heathens. These Demons buy or steal humans from the Premium Farms and hunt them for fun and excitement. They hunt them in their secret hunting reserve called Goldy Pond. Aristocrat Bayon hunts for fun while Archduke Lewis is known for his hunting skills, who hunt for excitement. The demons eat human meat after each hunt.

Diet
So far, the only thing known to be eaten by them, are humans from Premium Farms and Factory Farms. Though, a picture has shown that shows the demons surrounded by other foods like chicken, sausage, grapes, apples, bread, wine, and cats.

The Demons offer the premium-grade quality food to a certain demon they worship.

Trivia

 * Although they are referred to as demons by the orphans, there have been people who are denial to calling them demons. Whenever they say demon, the word is quoted or they call them by a different term:
 * Sister Krone's response to Emma and Norman: "The 'demons'? Oh, you mean them?"
 * Sonju, similar to Krone, stated: "The ancient contract between human beings and 'demons', sealed so long ago. We live in the half allotted to the 'demon' side back then."undefined
 * When a person on the human side made a proposal to cease the fights between humans and demons, he stated: "Human beings shan't hunt 'demons' anymore. In return, 'demons' shan't hunt humans either. This world we live in shall be divided between both."undefined
 * "Heathen" means someone who does not belong to a widely held religion as regarded by those who do. This might explain how heathens like Sonju and Mujika are only a minority out of the vast majority of demons that eat humans.
 * The wild demons/man-eaters are ranked 20th in the Popularity Poll that was announced in Chapter 88 of the Manga.