King of the Night

The King of the Night (夜の王, Yoru no Ō?) was a deceased young man who was brought back to life as a zombie by Eucliwood. His earth-bound alias was "Yoruno" (夜野?).

Appearance
He has pale gray hair and yellow eyes. When meeting with Eucliwood, he wears a red t-shirt with black slacks. In the final episode of season 1, he wears a fur coat with a gray t-shirt and pants.

Personality
Although initially being delighted with his immortality, Yoruno eventually grew to view it as a fate worse than death, turning him into a cold and bitter man. He wished for Eu to end his eternal life and was willing to go to extreme lengths in order to do so, despite knowing that she had killed a lot of friends in her past and didn't wish to kill anymore.

Despite his cold attitude, Yoruno had a great fondness for penguins, going so far as to ask Eu to bring him back as one as his final wish.

Plot
Prior to the events of the series, he and Eucliwood formed a very strong relationship, while he gained power and rank as a notorious figure in the Underworld. At a certain point, he became filled with malice and ambition, and went as far as killing a Seventh Abyss, one of many high-ranking individuals that were associated with the upper echelons of Underworld society. Eucliwood, horrified and saddened by what he had done, rejects him and attempts to destroy him.

Later, while investigating some recent serial killings alongside Kerberos Wansard, Ayumu is first informed of the King of the Night's existence. During the course of the conversation, the Megalo tells him that the serial killer had been killing people, taking their souls, and sacrificing them to the King of the Night, who would in turn bestow both tremendous magical power and a variety of specific ways of using and manifesting that power. Just before he can finish his explanation, Kerberos is destroyed by Kyoko, who had chosen to manifest at least one of those powers, namely the glowing eyes that Megalo possess.

After Ayumu defeats Kyoko a few days later, the King of the Night makes his first direct contact with him and Eucliwood, revealing his involvement in Kyoko's rampage, making it clear that many of her powers were granted by him. After he teleports Kyoko away, Eucliwood informs Ayumu and the others that The King of the Night is a zombie, one that she had thought that she had eliminated. Later, when Ayumu inquires further, she tells him about his downward spiral and her botched attempt to kill him.

A number of days later, after Ayumu and company meet Yuki Yoshida and spend an outing together at a mall, Eucliwood stumbles into King of the Night, who had been working at a pet shop in the same mall. Surprised by this, he takes her to an observation platform and recounts the past, and taunts her about what he wants from her. During the following conversation, Eucliwood becomes agitated, attacks him, and loses enough control of herself that she summons a gigantic version of her favourite doll, which nearly crushes Yuki and Haruna to death.

Eventually, Ariel intervenes, assuming that King of the Night had attacked Haruna, which he quickly puts aside as Eucliwood's doing. In response to the doll's attack, the magical weapon "Manticore" is automatically summoned by Yuki, nearly killing Ayumu's friends before he manages to persuade her to return to her senses. Once this is done, King of the Night strikes Ayumu with lightning and teleports away, with Ariel in pursuit.

Because of his now known presence and the danger it represents, Eucliwood leaves Ayumu's home and reluctantly joins King of the Night for the sake of their safety. During the search, Ayumu stops by the convenient store where he had first met Eucliwood, and meets King of the Night in person for the first time. Angered by this, and following a tense and hostile conversation, Ayumu tells the recently arrived Haruna and Seraphim that he vows to kill King of the Night.

Ayumu immediately attempts this, but is unable to touch let alone harm the King of the Night, who uses his signature black mist power, which can teleport its target as well as obliterating it. He also summons the Megalo-derived debilitating smog, weakening Ayumu's allies and firing a blast of the mist to finish them off. At this point, both Yuki and Sarasvati, Seraphim's superior, intervene and drive the King of the Night away.

Later, he continues his custody of Eucliwood, under the continued threat of killing her friends if she doesn't comply. She comes to his earth-bound apartment, which is later invaded by Ayumu and allies, including the nearby vampire ninja clans. After a tense but otherwise peaceful meal and conversation, he kidnaps Eucliwood while planting a bomb on Haruna, which forces Ayumu to take the bomb and and become consumed by the explosion at a safe distance.

After the explosion, which has knocked Ayumu unconscious and scattered his body parts, his allies reluctantly find and reassemble his body, which continues to be dormant despite regenerating. As Haruna and Ariel try to wake Ayumu, Seraphim is fatally wounded by King of the Night as Eucliwood passes by the house, but is quickly revived by the necromancer's infusion of blood. King of the Night and Eucliwood quickly depart, leaving a weakened Seraphim, found by Haruna and a resuscitated and resolved Ayumu.

Together, they leave in pursuit, finding the King of the Night and Eucliwood at the famous Tokyo Tower. There, Eucliwood involuntarily summons a large mask-Megalo to hover over the city, which continuously expels lost souls and even whale Megalos, which will destroy the city if they are not stopped. Seraphim plays her newly-acquired violin to hold the incursion at bay, but is quickly overwhelmed, only to be supported by her fellow vampire ninjas.

Concurrently, Ayumu and Haruna corner the King of the Night, demanding that he release his captive. After a tense standoff, Haruna's chainsaw reenables her Masou-Shoujo powers alongside Ayumu's, allowing them to both transform and attack the King of the Night, who blocks their attack with his black mist. His defense is so potent that it forces Ayumu and Haruna to both go to 1000% of their powers, which ultimately overpowers King of the Night, and causes a large explosion.

This explosion of conflicting energies teleports Haruna away and dispels the transformations, leaving Ayumu to face his adversary alone. Over the course of the brutal fight between the two zombies, which rages back and forth through the interior of the tower's observation deck, both of them angrily recount their feelings and relationship with Eucliwood. King of the Night stubbornly claims that he knows her better than Ayumu, noting the vast difference between the two relative to how long either have known her.

Ayumu furiously retorts by declaring that despite his long-term relationship with the necromancer, he has never understood her at all, knowing nothing about her nature as a person, even seemingly trivial things such as her favourite food, her smile, and more important things like her attitude towards life. Surprised by the truth in these statements, he angrily kicks Ayumu with 700% of his strength, which soon follows with Ayumu responding in kind with a full 800% strike, which breaks King of the Night's right arm.

As Ayumu continues his tirade, he further unleashes his full-strength assault, breaking bones, and spraying King of the Night's blood everywhere. Ayumu ultimately overpowers him both by declaring that he won't allow someone who had given up on life to tell him that he doesn't know Eucliwood, and by simultaneously punching through King of the Night's head. This splatters his brain and cranial fluids onto the window behind him, and Ayumu is about to continue, but is stopped by the anguished necromancer.

As the two zombies end their struggle and heal from their wounds, King of the Night tells Ayumu both not to blame Eucliwood for what had happened, and that he too will understand the drawbacks of immortality just as he did. Ayumu denies this, saying that his recently-acquired companions have added new and essential value to his now immortal life, and that he will never be a malevolent, melancholic, and lonely failure like King of the Night. Upon hearing this, King of the Night finally acknowledges both these facts, and the weight of his wrongdoings.

At this point, he succeeds in persuading Eucliwood to end his life, which she does with a quiet incantation, which causes him to dissipate into a purplish, sparkling haze. Before he completely vanishes, he begs for forgiveness for his crimes, and pleads for her to reincarnate him as a penguin, which she acknowledges. His now expired body and soul return to the Underworld through the now sealing and closing gate alongside the Megalo incursion, ending his threat and the recent Megalo attacks once and for all.

Abilities

 * Immortality: Since he is a zombie, just like Ayumu, he is immortal. Eucliwood is the only one who can put an end to his eternity.
 * Super Strength: Just like Ayumu. He is not limited to the amount of muscle power he uses as a human, and is able to increase his strength by saying the numbers. During his fight against Ayumu, he was able to increase his power up to 500%.
 * Black Mist Manipulation: His main ability is the power to control black mist. He usually uses them to surround his opponent, and cover the scenery, before attacking them. His black mist is also capable of acting as barrier to block the opponent's attack.
 * Teleportation: Through his black mist, he can also teleport to a different location.
 * Possession: He is able to take over someone's body, and temporary use them as a media to speak. As demonstrated when he took control over Kyouko.
 * Parasite Bomb: He has been shown to be able to set a bomb which can move from one person to another.

Trivia

 * His earth-bound alias, Yoruno (夜野?), is a play on the Japanese reading of the word King of the Night (夜の王, Yoru no Ō?).