Darkness Devil

The Darkness Devil (の) is a devil that embodies the primal fear of the dark.

It serves as the secondary antagonist of the International Assassins arc.

Appearance
The Darkness Devil's body is made up of many emaciated human bodies, with two bodies acting as its legs and four other human bodies acting as its torso, each having a unique face: the one immediately below the neck has no eyes, nose and a vertical mouth, the second head has open eyes and a stitched mouth, the third one has no nose, an open mouth and stitched eyes, and the fourth one has no eyes and a somber expression. Its head is akin to that of a pterodactyl with curved horns. The first human body has its arms stretching outwards holding what seems to be a cape of darkness.

Personality
Nothing is currently known about the Darkness Devil's personality, except that it will attack anything it perceives as a threat. Even though it is almost entirely silent, it is shown to be intelligent and capable of reasoning, as a human can make a contract with it. Like other devils, it displays high animosity towards Chainsaw Man because of the threat he poses.

International Assassins arc
The Darkness Devil appears shortly after Denji along with several other Devil Hunters and assassins are transported to Hell by the Hell Devil. It emerges out of a door in the sky and immediately attacks, removing all of the group's arms. The Doll Devil, through Tolka, offers the Chainsaw Devil's heart in order to gain the power to kill Makima. The Darkness Devil fulfills its end of the request by feeding a piece of its flesh to Santa Clause on Earth.

With the contract complete, the Darkness Devil picks up Tolka and decapitates him. Kusakabe tries to use the Stone Devil against the Darkness Devil, but is killed with the Stone Devil when the former seizes and destroys it. Beam successfully revives Denji by giving him his blood and pulling his chainsaw cord, but is sliced into pieces by the Darkness Devil.

Quanxi and Tamaoki charge at the Darkness Devil simultaneously and try to kick it but the Darkness Devil swiftly scythes through them both, catching Long, Pingtsi and Power in the aftermath of its attack as well. The Violence Fiend, who has had his mask removed by Kobeni Higashiyama, leaps in from above to try and kick the Darkness Devil but is pierced multiple times. Denji leaps in and unsuccessfully attacks the Devil with a chainsaw arm.

The Darkness Devil clasps its hands together and Denji's body contorts painfully, disabling him. The Violence Fiend leaps in once more desperately with his severed arm held in his mouth, but the Darkness Devil summons a black blade which pierces the Violence Fiend and completely destroys his body. It then kneels down over Aki Hayakawa and looks at him.

The Darkness Devil looks at the Angel Devil and causes both him and Aki to start bleeding severely. Just as it reaches down to grab Aki, Princi emerges from the ground nearby and unsuccessfully attacks the Darkness Devil, losing several of her limbs in the process. Makima instructs Princi to summon her to Hell and she faces off against the Darkness Devil.

The two of them point at each other; Makima's finger breaks and the Darkness Devil begins to bleed and stoops over. As Makima's arm contorts and breaks, she offers Tolka's body to Hell Devil in return for bringing them back to Earth. The Darkness Devil conjures its black blade once more and pierces Makima with it just as everyone is transported back to the department store.

Abilities
The Darkness Devil is described as a transcendent being — one of the "primal fear" devils that have never experienced death due to being so powerful; embodying a primal fear, it can be assumed that the Darkness Devil is almost as old as humanity itself. Indeed, the Darkness Devil's power is such that ordinary devils and humans will supposedly die the very moment they draw its hostility.

Naturally, it possesses all of the standard devil abilities such as blood consumption, contract creation, etc. The only contract with the Darkness Devil seen so far was made by Santa Claus: in exchange for delivering the heart of Denji to Hell, Santa Claus gained a small piece of the Darkness Devil's flesh that allowed the assassin to manipulate their body in darkness and amplified their total power vastly.

Physical Abilities

 * Immense Speed: The Darkness Devil can travel and attack at high speeds. It was able to appear in the midst of several devil hunters, including Quanxi, without any of them being able to perceive its movements. By using its multiple arms it could slice through several fighters before they could react, and dodged or otherwise counteracted attacks with ease.
 * Immense Strength: The Darkness Devil has shown to be able to lift its targets with great ease and damage them easily by swinging its arms around.
 * Immense Healing Factor: While in the dark, the Darkness Devil can rapidly regenerate from a powerful attack from Makima.

Devil Powers

 * Nigh-Absolute Immortality: As revealed by the Falling Devil, a primal fear devil cannot be killed with any conventional means — that is, any means currently available to humanity.
 * Darkness Manipulation: As the embodiment of fear of darkness, the Darkness Devil has the ability to manipulate darkness. It can transform into a mass of darkness and envelop the surrounding area in darkness, manifesting the bodies of 10 bisected astronauts as it does so.
 * Blade of Darkness: The Darkness Devil can also conjure a large blade with bells attached to its hilt that can be telekinetically controlled to attack its enemies. Once it makes contact, any being will hemorrhage violently once the bells ring.


 * Force Manipulation: The Darkness Devil has been shown to offensively manipulate an unseen force in various ways similar to the Control Devil. With this ability, the Darkness Devil can sever the arms of various humans, fiends and devils, cut them into pieces just by pointing at them or through movements of its many arms, or brutally obliterating their body after uttering an unreadable word. It can also induce violent hemorrhages on those it watches. However, Makima is shown to be stronger in this ability, as she can heavily damage the Darkness Devil only by pointing her finger at it. It seems that the power of this ability can be increased by switching gestures, as the Darkness Devil completely twisted Makima's arm in the second attempt while praying with two of its hands despite the Control Devil trying to block the attack with all five fingers.
 * Regeneration Nullification: Those who are dismembered by the Darkness Devil appear to have their regeneration nullified. The extent of this ability is unclear, as Kobeni and Power were able to return to normal, only one of Aki's arms was reattached, and Angel's arms were permanently lost, with him stating that he is unable to regenerate them and can no longer be a devil hunter.


 * Devil Manifestation: The Darkness Devil appears to be able to forcefully manifest other devils and kill them instantly. In the case of the Stone Devil, this also resulted in the death of the human they contracted with, Kusakabe.

Weaknesses

 * Light: Because Denji was able to overpower and damage a Darkness-empowered Santa Claus by lighting himself on fire (thus producing light and weakening the powers given to her by the Devil), it can be inferred that the Darkness Devil's powers can be counteracted with light. However, as a Primal Devil, it would likely be insufficient to kill them.

Trivia

 * The Darkness Devil's rankings in the Popularity Polls are as follows:
 * The Darkness Devil ranked 27th in the Second Popularity Poll with 1,575 votes.
 * Despite Santa Claus being accused of killing the people in the battle in Hell, even if she would not care if they were alive or not, it was the Darkness Devil who truly was responsible for their deaths as Santa Claus was only indirectly responsible.