DEMONS

Also called Monsters or Devils, they are creatures that inhabit the Sage Realm.

They exhibit animalistic traits and come in a variety of shapes and abilities. Usually, the stronger the demon, the more human-like they appear. They have a much longer life expectancy than humans, with many of them capable of living for over thousands of years.

With more than 12 billion combatants [11] during Wukong's reign, they are a densely populated species.

They are very likely inspired by Asuras, power-seeking demigods/antigods/demons that often only follow their desires and wage war against the gods.

The list of known demons is here.

Demon Kings

Monsters are ruled over by the Demon Kings, immensely powerful demons who are capable of slaying high ranking gods.

The 9 Demon Kings were a brotherhood whose goal was to gain independence from the gods of the Heavenly Realm.

Known Demon Kings, ranked in strength by the series: [1]

The Monkey King, Jin Mori
The Oxen King, Uma
The 201st Dragon King, Junior
The Roc Demon King, Garuda

Garuda defected and sided with the gods during the First Heavenly War, while Junior remained neutral.

There were 201 Dragon Kings, Ogre being the first Dragon King and Junior being the last one.

Demon Races

There are many types of demons inhabiting the Sage Realm:

Mount Hwagwa Monkeys
Minotaurs
Dragons
Haetaes
Mount Hwagwa Tigers
Rabbits
Deer
Foxes
Titans and other alien-like creatures

Mt Hwagwa Monkeys

They are described as being very gentle creatures that, when startled, turn violent. [2] They were ruled over by Jin Mori, and, during his absence, a fake Monkey King named Mihu presided over them. They accompanied Mori throughout the majority of the wars, including the First and Second Heavenly Wars as well as the conflict between Okhwang and Hui Mori.

Despite being categorized as a Mt. Hwagwa Monkey demon, Mori was not born among them; Rather, Gaia created him from her corpse. With the exception of his irises, he is the only demon known to exist who is identical to a human in appearance.

They experienced great famine following the First Heavenly War's defeat and were subjugated by the gods via Mihu, who served NOX. As a result, King Uma declared war on them, enraged that they were giving them their resources. [3]

Similarly to Jin Mori's "human" eyes, the monkeys' eyes are black with bright gold pupils which create crosses that extend all the way to the irises' edges whenever they're irritated or excited.

This causes them to succumb to their "Original Sin", a state of rage and extreme aggression. During this state, they emit a terrifying aura and their power is increased.

Some monkeys have the ability to enter "Combat Mode" in which their appearance becomes more human and their abilities are significantly enhanced.

Mount Hwagwa Monkey Soldiers

Mihu using Combat Mode to appear more human

Minotaurs

As their name suggests, they have the body of a human and the head of a bull. They have hooves instead of legs, a tail and their skin is red in color. They seem to be attracted to horns, considering that the bigger they are the more beautiful. Their powers originate from their horns. [9]

They are ruled over by the "Cow Devil" King Uma, Jin Mori's sworn older brother. She appears the most human out of all of them, but she is twice as tall as the average person (her real form is about 10 times bigger) [10], has ears, teeth, a tail, and enormous horns that resemble those of an ox.

They were defeated in the First Heavenly War and due to the Mount Hwagwa Monkeys being ruled by a replacement which served NOX, the relationship between the two species significantly worsened.

Minotaurs

Dragons

They're the oldest species of demons. The First Dragon King, Ogre, was the first dragon who even lived among dinosaurs. They're Garuda's favourite meal. [4]

Most dragons used to dwell within The Dragon King's Palace, where the weapons made out of their own bones and their souls are hid and protected. After Tathagata was killed on the moon, Xiaochen and Ryong brought the dragons on the brink of annihilation. [5] The surviving dragons stayed hidden within different parts of the Human Realm.

Dragons make everything out of their own bones. The stronger the dragon, the better their bones are. They're easier to shape and they're even more durable than the Barbadium in the Heavenly Realm. [6] They have high regenerative capabilities and are by default very strong demons.

The Dragon Kings serving their master, Jin Mori

Haetae

Like other demons, they're residents of the Sage Realm. They're blue dog-like creatures with a single horn on their forehead and branched horns. They typically have a pipe in their mouth and wear a top hat. They can range in size from that of a dog to that of a human or even a tall building. They are very loyal once their trust is gained and are regarded to be sacred animals together with dragons. [7]

Their tears and saliva have healing properties. Haetaes can partially heal wounds and alleviate the effects of the Divine Pellets. They can cure serious illnesses like brain damage or blindness by paying a higher price, such as giving up their lives. [8]

Han Daewi's Haetae was shown to have a human form that resembles a young girl with teal hair and big, yellow eyes who is dressed in a blue Hanbok and wears her signature top hat.

Haetae's human form

Baby Haetae

Adult Haetae

Tigers, Rabbits, Deer, Foxes, Titans and other creatures

Not much is known about them.

The tigers live in the Mount Hwagwa area.

The only characters introduced from the deer and rabbit demons are Deer and Rabbit respectively, each slaughtering their entire races in order to become Tathagata's Apostles.

Hojosa, the Nine Tailed Fox, is the only character introduced as a fox devil.

Titans and alien-like creatures exist outside Oraeguk on different planets of the Sage Realm. For the longest time they have tried to enter the Heavenly Realm as an Apostle but were defeated by the Gatekeeper.