Derieri

is an elite warrior of the Demon Clan, serving directly under the Demon King as the Purity of the Ten Commandments.

Appearance
Derieri is a toned woman with long, spiky hair. She wears no clothes, instead covering about half her body in her own darkness. She has demon markings on her left check which resemble a beast's open mouth with a circle in the center.

After her battle with Nerobasta her hair is made significantly shorter and more tomboyish. Monspeet later trims and evens it out for her.

Personality
Derieri has a rather apathetic and nonchalant demeanor. She has a very strange way of speaking, usually prefacing her comments with. Which roughly means "long story short" or "in other words".

She harbors a great hatred towards the Goddess Clan, possibly due to a situation where they broke a treaty and slaughtered many demon prisoners of war, and seeing one is one of the few things to change her normally apathetic demeanor. Going by her reaction to Elizabeth Liones she seems to especially hate Elizabeth.

3,000 years ago
Along with the rest of the Demon Clan, Derieri was sealed away by the Goddess Clan after losing the Ancient War against the other four races (humans, fairies, giants and goddesses).

Albion arc
After Hendrickson managed to remove the seal, Derieri and the rest of the Ten Commandments appeared before the terrified former Great Holy Knight and Fraudrin in Dreyfus' body with Zeldris uttered Meliodas' name as if he knew him. After being informed by Fraudrin of the current events in Britannia, Zeldris suggested that they should head for Edinburgh Hill for recuperation of their severely drained magical powers due to the seal they're trapped in, which everyone agreed and left Zhuhur Valley by flight, leaving a terrified Hendrickson.

Arriving at Edinburgh Castle, Derieri and her fellow Ten Commandments find a castle in ruins and a giant hole, the latter of which, they conclude that it was Meliodas who caused. After Galand left to take a look at one of the destroyed Albions, she and the others discuss how to recover their power faster, and begin to collect souls to eat, as a way to both recover their magic faster as well as exterminate the humans. When Galand returns and explains he killed Meliodas, Derieri is asleep in Monspeet's lap.

Istar arc
Later, Meliodas unexpectedly pays the Ten Commandments a visit, easily defeats Galand, and warns them if they get out of line, he and the Seven Deadly Sins will crush them. In response Zeldris orders them all to head off to more quickly regain their magic and exterminate the other races. She and Monspeet then head to a town known as Bellford.

Great Fight Festival arc
She and Monspeet continue their purge in the north of Britannia, having devoured the souls of almost every person in nine cities and villages and showing no signs of stopping.

Later on on she, along with the other Commandments, arrive to aid Drole and Gloxinia, who are facing off against Meliodas. After Grayroad has ensured that Meliodas cannot escape, Derieri immediately goes on the offensive exchanging blow after blow with Meliodas. Due to her power, Combo Star, she quickly gains the upper hand and seemingly causes his demonic powers to fade, renders both his arms useless, and then throws him into Monspeet's arms. She watches as Meliodas almost cuts Monspeet's head off, and makes a remark he does not even want to understand. After Meliodas is defeated, she comments that she feels someone watching them, and wonders if they really should just let them be.

Defensive Battle for Liones arc
As the Ten Commandments move to take Castle Liones, Denzel arrives, announcing to protect the kingdom by killing the demons, and allows the goddess Nerobasta to use his body as a vessel in order to fight the Commandments. Enraged at the sight of a goddess, Derieri says she will kill her alone.

Shortly after entering Denzel's body, Nerobasta states her name and rank, and asks what mission she has been tasked with. Upon seeing demons, and specifically Derieri she becomes enraged that the seal on the Demon Clan has been broken. When Deathpierce explains the situation, she refuses to help and attempts to flee, killing a red and gray demon on her exit with her attack Ark. The onlooking Monspeet muses that the usage of light magic is typical of the Goddess Clan and the opposite of the Demon Clan's own darkness.

Derieri takes to the skies and Nerobasta, following her, attempts to kill Derieri with Ark, but she negates the attack with her darkness, merely having most of her hair disintegrated. Nerobasta then attempts to behead Derieri, but she uses her darkness to cover her neck, breaking the blade.

Nerobasta, realizing she's outmatched, attempts diplomacy, stating she understands why Derieri might hate her and her people for breaking the treaty and killing demon children, but before she can finish, Derieri bifurcates Denzel's body, killing her. During the battle to take Liones, Derieri and Monspeet notice a strange disturbance and go to see what it is. When they arrive, they find a giant pig causing havoc, being ridden by some unusual travelers. Originally curious at Elizabeth Liones's resemblance to a person she once knew, Derieri later became enraged when Elizabeth uses Ark on her and attempts to kill her only to be blindsided and seriously wounded by Meliodas. She falls off the pig and Monspeet rushes to her side.

Once Derieri regains consciousness, she spends a significant amount of effort to heal her wound with her darkness. Getting over the initial shock of seeing Meliodas alive, she devises a plan to kill him again. She tells Monspeet that she will distract Meliodas, and when the opportunity presents itself, he should hit both of them with his strongest attack. Monspeet at first feigns ignorance of what she means, but she assures him that she will survive the attack as she believes that she is much tougher than Meliodas.

She then charges off and Monspeet summons many lesser demons to help Derieri build up her Combo Star ability. After hitting 51 demons, Hawk Mama and Hawk, Meliodas blindsides her again by pile driving her into the ground thus resetting her combo. Enraged, she begins attacking Meliodas again, screaming at the traitor, but he easily parries all of her blows until attack number 12, in which he resets her combo once again by dodging her punch and hitting her from behind.

Meanwhile, Monspeet positions himself in the sky right above the fight. As Derieri tries to build up new combos, which are continuously parried by Meliodas, the latter admits that he'd rather not kill his former comrades. As Monspeet then unleashes his Kaijinryu, Meliodas specifies that his previous statement is something the old him would have said and proceeds to kick Derieri into the sky. He then activates his Black Mark and uses Full Counter with a sinister smile on his face, telling her to die. Monspeet rushes into the fray to save her, but they are both consumed by the rebound.

Abilities and Equipment
Like all members of the Demon Clan, Derieri is able to utilize the mysterious jet-black power of darkness, as previously seen by Meliodas, to form wings for flight.

As a member of the Ten Commandments, she is exceptionally powerful. Her aura is so powerful that it made the normally calm Hendrickson sweat in fear, simply by being in their presence. Derieri was the first demon to showcase the power to devour the souls of any of the other races, leaving them as empty husks.

Derieri demonstrates expertise in hand-to-hand combat, overwhelming someone of Meliodas' caliber and even breaking both his forearms with her ability, Combo Star. She also possesses the speed to outpace Meliodas with a sheer volume of attacks and hitting him quickly 54 times in a matter of seconds.

Abilities

 * Derieri's innate power. As long as she continues attacking without interruption, each consecutive blow receives an additional 200,000 pounds of force compared to the previous one.

Commandment
The Demon King bestowed Derieri with the Commandment of. Its curse and activation condition are currently unknown.

Monspeet
Derieri and Monspeet seem to be very close, they are always in each others company, and he attends to her needs, such as allowing her to rest on his lap. It was also shown that despite her talking in very few words, he perfectly understood what she is thinking in full depth even if she does not go into detail and talks in a plain yet very awkward way.

Great Fight Festival arc

 * Meliodas vs. Ten Commandments: Win

Defensive Battle for Liones arc

 * Derieri vs. Nerobasta: Win
 * Meliodas vs. Derieri & Monspeet: Lose

Current arc

 * Ten Commandments vs. Four Archangels: TBA

Trivia

 * According to the official fanbook:
 * Handedness: Left-handed
 * Birthplace: Demon Realm
 * Special ability: Beating up people in one-on-one fights
 * Hobbies: Playing in the water
 * Daily Routine: Skipping out
 * Favorite food: Souls, meat
 * Dream/Hope: Conquering Britannia
 * Charmpoint: Abs
 * Her name is likely to be a reference to the French word "Derrière", literally meaning ass, directly relating to her unique way of talking.
 * The author, Nakaba Suzuki, has stated that she, along with Galand, are his personal favorites design wise among the Ten Commandments.

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