Demonic Beast Guivre

Demonic Beast Guivre (魔獣ギーヴル,) was the singularity that existed inside Paul Verlaine, which when unleashed transformed him into a singularity life-form. Because of its cataclysmic potential, its creator Pan named it after the mirror image of the malevolent god and original demon Guivre.

Appearance
In its true form, Guivre was a gargantuan black beast that appeared reptilian and whose head resembled the beast Guivre, albeit with two glowing crimson red eyes that were positioned exactly like a human's. With thick arms, a robust torso, and a massive mouth, Guivre did not possess any organs nor was it made of physical matter, but rather it was the single location where limitless energy stored in the singularity condensed into. It also had a dinosaur-like body, claws, and a black tail. Its feet were enormous enough to flatten roads, highways, and even an entire hill.

In its early stages of manifestation, Guivre's body pulsated and kept on growing until it obscured the moonlit sky. Eventually, it grew comparatively colossal than the true form of Arahabaki. In general, Guivre looked nothing like any living being and was too bizarre for human comprehension.

Personality
Incapable of coherent thought, Guivre was far too sinister to be called a god and was the embodiment of chaos more than a god of destruction. No more than a pool of hatred, it reacted to emotions and particularly responded to hatred, which propelled it automatically move to attack anything hostile, and it could not discern which party was more dangerous than the others and who it would prioritize attacking.

Powers and Abilities

 * Hatred Embodiment: Guivre responded to hatred and therefore reacted to anyone and anything that reacted to its presence, mindlessly attacking them possibly until it ran out of energy. When it clashed with Arahabaki, black flames of hatred spewed out of its wounds and instantly regenerated its injuries.
 * Limitless Energy: Guivre was a singularity that possessed an infinite amount of energy. Osamu Dazai theorized that it could run out of energy in a week, a year, or even "until the end of the world". In comparison with Arahabaki's rampage on Suribachi City, Guivre was believed to be capable of sinking the entirety of Yokohama if it unleashed the same power that Arahabaki unleashed.
 * Near-Invulnerability: Made of no physical matter, Guivre innately possessed no vulnerabilities on its form that could be attacked by mere humans or abilities. It could not be damaged with fire, ice, and firepower.
 * Gravity Manipulation: Similar with Arahabaki, Guivre could manipulate gravity in various forms and fashions with high offensive intensity.
 * Gravitational Spheres: Guivre could breathe beams of gravity to annihilate any target along with the surrounding terrain until nothing remained. It could also unleash gravitational spheres of darkness powered by hatred.
 * Black Hole Generation: Guivre could shoot a black hole like a laser, able to hollow land in a straight line like creating a cliff with an abysmal pit. It could repeatedly generate black holes and once created at least 20 black orbs almost simultaneously.
 * Graviton Radiation: When incinerated by the ability weapon Annihilation, Guivre was able to withstand its intense heat by absorbing the singularity energy from the weapon's fiery sphere.

Background
Pan, a French researcher, discovered how to create artificial abilities using self-contradicting singularities and successfully made Black No. 12, whose self-contradicting singularity was known as Demonic Beast Guivre. It could be unleashed when a persona model's control, specifically Verlaine's, was stripped away whether willingly or forcibly.

King of Assassins Incident
Verlaine tapped into Guivre's power when left with no choice against the Port Mafia's ambushing forces and succumbed to Brutalization. After he annihilated numerous operatives with his calamitous powers, Chūya Nakahara and Adam Frankenstein worked together to subdue Verlaine and thereby Guivre's rage.

Soon after, Guivre was forcibly unleashed from Verlaine after N remotely fired metallic particles made from the same ability metal powder that Pan used to control Verlaine in the past. Similar to when Arahabaki was unleashed nine years ago that turned Suribachi City into a crater, Guivre caused a calamitous rampage throughout a forest some distance from Yokohama. It annihilated the Mafia's forces and various other ability users and destroyed the terrain it spanned, eventually aiming to make its way towards Yokohama. Before its manifestation, Chūya and Adam were sucked into its core, where Verlaine showed Chūya a memory from nine years ago on how to defeat Guivre.

With this knowledge, Chūya planned with Dazai to open his own Gate and unleash Arahabaki's boundless energy on Guivre. In the ensuing battle, Arahabaki Chūya's gravitational spheres continually damaged Guivre, resulting in a battle of gravity. With its regenerative abilities and greater power, Guivre gained the upper hand against Arahabaki Chūya, until remaining Mafia forces aided to distract the beast to give Chūya time to recover. Arahabaki Chūya soon finished off Guivre as his negative energy canceled out Guivre's energy, until Guivre began to disintegrate and crumble to pieces.

Legacy
After Guivre's demise, Verlaine had exhausted every internal energy he possessed and slowly ceased to exist. However, Verlaine soon found himself in Arthur Rimbaud's subspace, where Rimbaud used his own ability to resuscitate Verlaine and replace Guivre with a self-contradicting singularity he generated as Verlaine's new singularity.

Trivia

 * In French folklore, a is a mythical serpentine creature like a dragon that had venomous breath and prowled Medieval France's countryside. It was believed to be a chimerical beast having the body of a skinny serpent, the head of a horn dragon, legs like those of a bird of prey, and membranous wings like those of a bat.