Demon Clan

The is one of the five major races in the world of Nanatsu no Taizai.

Overview
According to the Lady of the Lake, the Demon Clan and their realm were created by the Demon King, after he was created by Chaos, alongside the Supreme Deity and the Sacred Tree.

3,000 years ago, the Demon Clan constantly clashed with the Goddess Clan due to the bitter rivalry between their two rulers. Their elite group of warriors are the Ten Commandments, who were handpicked by the Demon King due to their power. Many demons consider themselves above those of other races for their great power, especially humans. However, the two legendary clans were largely evenly matched and thus a tentative balance was created. At some point in time, the Goddess Clan broke a treaty with them, and even slaughtered many women and children they were holding as prisoners of war.

At some point, the Vampires became allies yet subservients to the Demon Clan. When the leader of the Commandments, Meliodas, betrayed his own people for his alliance and relationship with the powerful goddess, Elizabeth, and severely crippled their strength by killing two members of the Ten Commandments when escaping, it indirectly caused two events: The Goddesses seized the opportunity to destroy the Demons once and for all, who waged a great war against the Goddess Clan after they allied with the Giant Clan, Fairy Clan and eventually the humans. The Vampire Clan decided to rebel during this time as the Demon Clan got weaker, but still got single-handedly defeated and sealed away.

As a result, the Demon Clan was ultimately defeated by the Goddess Clan and their allied clans, being sealed away in the Coffin of Eternal Darkness for many years. In spite of their fate though, a few demons managed to escape from or avoid the seal completely, namely a single Red Demon, a single Gray Demon, and Fraudrin of the Ten Commandments. The latter would spend sixteen years trying to find a way to break the seal and to resurrect his clan, so they could take over the land of Britannia.

The other nine members of the Commandments were eventually resurrected when Hendrickson manages to break the seal. Their biggest threat on their way to conquer the continent once more was in fact one of their own kind; Meliodas, their former leader and the oldest son and heir of the Demon King, who was still alive thanks to the Supreme Deity's curse of eternal life.

After organizing a fighting festival to lure Meliodas into a trap, they managed to kill him and begin the conquest of Britannia in the following month, taking the souls of every human they come across in order to regain their strength. However, when the Ten Commandments tries to conquer the kingdom of Liones, they are eventually stopped by the group formed with the goal of destroying them, the Seven Deadly Sins, as well as Meliodas who was resurrected due to his curse.

The remaining members of the Ten Commandments, Zeldris and Estarossa, took refuge in their established base in the kingdom of Camelot, where they sacrificed human souls in order to completely break the seal and liberate the entire Demon Clan. Eventually, the fearsome Cusack and Chandler joins them, as did Meliodas, who had decided to become the new Demon King to break the curse on him and Elizabeth after making a deal with his brothers.

When the Four Archangels of the Goddess Clan "revive" to join Elizabeth, the Seven Deadly Sins and the humans against them, the Demon Clan faces a new Holy War.

While the lower limbs of the Demon Clan fight on the battlefield, Zeldris, Estarossa, Cusack and Chandler face the united forces of the Seven Deadly Sins and the Four Archangels. Estarossa is then revealed as the fourth member of the Archangels, Mael, whose identity had been altered 3,000 years ago by the demon Gowther. After removing Mael from the madness caused by the Commandments he had absorbed, he joins the fight against Zeldris and the unified Original Demon. Although both are defeated, Meliodas, who had managed to absorb the ten Commandments, is converted into the vessel of the Demon King.

Finally, with the defeat of the Demon King, the remaining members of the Demon Clan withdraw from Britannia, thus concluding the Holy War. However, the Demon King manages to revive once again by taking Zeldris as his new vessel and plans to conquer Britannia himself as its new god. To save his brother, Meliodas travels with Elizabeth to Lake Salisbury to stop his father and nearly loses Zeldris forever until the rest of the Sins appear and help Meliodas to convince Zeldris to fight against his father, alongside Gelda who appears to help free her lover from the Demon King's grasp and force him out of Zeldris' body.

In a last-ditch effort to destroy his traitorous sons, the Seven Deadly Sins, Elizabeth and Gelda, the Demon King uses the Commandments to possess the ground of Britannia itself but the Sins combine their energy together to destroy his subsitute vessel and Meliodas destroys the Commandments forever by sacrificing his godly power to ensure his father can never return again, thus ending the fight once and for all.

While most of the Demon Clan returned to the Demon Realm, those who abandoned the battle during the Holy War enstablished a village on Dalflare Range.

Appearance
Many of the Demon Clan members have monstrous appearances. Lesser Demons seems to be quite diverse, each kind with its own appearance, easily identified by colors, such as Red Demons or Gray Demons.

However, Demons of higher ranking have mostly humanoid appearances, namely the Ten Commandments or Meliodas. Though, there are exceptions, as in Grayroad's case. Human-like demons can be distinguished from Humans by their pitch black eyes and black markings on their skin. However, when not in possession of a Commandment, the Demon princes Meliodas and Zeldris possess green eyes. Similarly, Derieri eyes also become regular colored when willingly removing her dark marks.

Physiology
Unlike humans, Demons have more than one heart. The number of hearts varies, although upper-level demons have seven hearts. The removal or destruction of a single heart does not incur death, although it is painful. Destroying all their hearts, regardless of their strength, will kill them.

Some demons have black markings on their face, which vary from demon to demon. Because of its many uses, many demons find it convenient to keep their bodies or weapons cloaked in darkness constantly to various degrees, Demons that do such include members of the Ten Commandments Grayroad, Melascula, Derieri and Monspeet, as well as the highest-ranking demon Cusack.

Demons are capable of living 1000 years, having the second shortest lifespan of the five races, after humans. However there is some exceptions like Chandler and Cusack living 6000 years due to them being from two halves of the Original Demon

Drinking the blood of a demon may give non-demons enhanced strength and magical power, if they are compatible. If they are not, they will explode. Demonic blood may naturally or forcibly turn the drinker into a demon themselves, a process that can be reversed either by removing their demonic plant or through the power of the Goddesses.

However a non-demon can learn to control demon blood given some time to control it shown when Guila was able to take on a demom form after 16 years of controling demon blood within her and is able to use demon abilities such as Hellblaze.

Powers and Abilities
The Demon Clan is an extremely powerful race, only being on equal on power with the goddesses and being sealed by the cooperation of the latter with fairies, giants and humans. According to Chandler, a demon's power is at least two-fold greater at night.

Members of the Demon Clan share several common abilities:
 * Power of Darkness: Demons can create and manipulate a mysterious dark substance to enhance both their offensive and defensive abilities. It has been shown to form various weapons and to protect them from attacks that would otherwise cause serious injury. It can also be morphed into various shapes.
 * Enhanced Regeneration: They can use their darkness to piece together an injured demon's body and mend grave wounds, but are unable to regenerate destroyed hearts and any damage sustained accumulates unless one of them are similar to an immortal.
 * Flight: They may also use their own darkness to form wings, helicopter like blades, or simply for levitation, allowing them to fly.
 * A powerful, dark flame that never extinguish and is capable of negating regenerative abilities. It also can be invoked in the form of an enchantment.
 * Soul Stealing: Demons are capable of forcing the souls of living creatures (even other demons) out of their body either by chanting an ancient spell to do so in mass or by simply touching the person whose soul they wish to take. Although, it seems stronger-willed souls are more difficult to steal, as show by Meliodas who shows resistance to Melascula's ancient curses. Eating souls allows them to replenish their magic and also gives them access to the person's memories, but will destroy the soul itself.
 * Indura Transformation: A secret taboo skill, only known to and allowed for a few of the highest ranked demons, such as the Ten Commandments. The user makes a contract by sacrificing six of their seven hearts, their original form, and ability to reason in exchange for great power. It can only be performed by upper-level demons, and one must have a power level of greater than 50,000 in order to perform the technique without dying. Once transformed, the Indura will not stop until every last bit of its life force has been used up.
 * Control of Lesser Demons: Higher ranked clan members such as Chandler, Cusack, Zeldris, Gloxinia and Monspeet are shown to be able to command lower ranked demons into doing their bidding.
 * Possession: According to Sariel, high-ranked Demons, like Goddesses, are able to take human bodies as vessels and use them as their own. However, the vessel may have difficulty hosting these Demons, leading their bodies to undergo transformations or some abilities that are left behind.Unlike Goddesses who possess someone by consensus and use their own abilities through the vessel, Demons possess by force, and usually are unable to use their authentic power but that of the vessel.

Trivia

 * If the Demons were never sealed and lived normally, they would have died three times.
 * It can be seen that Demons are not resistant to psychic powers, like when Meliodas was fighting Diane, but it was really an illusion of Ruin. Another example is of Galand against Meliodas, Diane, Merlin and Slader, thinking that they were all already dead, being in reality an illusion of Gowther through Invasion at the last moment.