The source of magical powers. They used to be vampires, who were later turned into demons under certain circumstances.
- Horned Humanoid: Most demons (save for Mahiru) are depicted with horns on their heads.
- Humans Are the Real Monsters: Same reason as Vampires. Makes sense as most of them are former vampires.
- Laser-Guided Amnesia: Demons have no memory of who they were before they were turned. The only exception to this rule so far is Mahiru-no-Yo.
- Meaningful Rename: A demon's name is essentially a Japanized version of their original name and even sounds like it. Examples include Asuramaru (Ashera Tepes) and Shikama Douji (Sika Madu).
- Our Demons Are Different:
- They can be sealed in what the humans call Cursed Gear. Stronger vampires make stronger demons, which make stronger Cursed Gear. Through a contract ceremony, the human tries to convince the demon to give him/her power and if they are successful, the demon makes a contract with said human and becomes their Cursed Gear. The only reason demons form this contract is to have an opportunity to steal their host's body. In return, demons lend their physical abilities (e.g. Super Strength and Healing Factor) and Curse Power (the only thing that could overcome the regenerative skills of vampires) to the hosts.
- Demons are creatures born from passionate desire, so they appear at the age when they were most innocent and pure, when they felt that everything was possible.
- Demons feed off of desire, but are weakened by love. That's why it's difficult for humans to successfully form contract with demons; demons are capable of using the most passionate desires and emotions inside human heart to manipulate the potential hosts.
- There are two types of demons: Manifestation and Possession.
- Manifestation types demons have the convenient ability to remain in a smaller, more portable size or manifest into the full-sized weapon at will. They may have the power to cast blessings or curses. Manifestation is the state in which the user lets his or her contracted demon come out and be able to use its special power. This drastically reduces the defensive abilities of the host since the demon moves elsewhere. These types of demons work best at different ranges, and the type of ability varies.
- Possession types are demons whose malice is too strong, making it ferocious. They refuse to submit so easily and are mean and aggressive. They are hell-bent on possessing its user, and it is common for them to engage in close combat to display their might. They cannot change into a portable size or manifest. They are more well-balanced for offense and defense than manifestation-types because activating their particular capabilities does not leave their hosts vulnerable. They increase the physical strength and power of their user. They are typically limited to close-range combat or melee fighting. They are not supposed to have the special abilities seen with manifestation-type demons.
- There are several ranks in which demons are classified: Black Demons (which are the highest-ranking demons and thus the most powerful in terms of capability), Bodhisattva, Rakshasa, Dakini, Fiends, Wisdom Kings, Yaksha, and Myo-O (the lowest rank of demons). A person using a Black Demon is capable of killing multiple common vampires armed with second-class weapons at once and going toe-to-toe with a vampire city guard armed with a first-class weapon. It's still suicidal for them to engage in a one-on-one fight with even a lower-ranking Progenitor.
- Was Once a Man: Demons are either former humans who were born with demonic traits and/or after contact with a demon or former vampires, who were former humans themselves, transformed under certain conditions.
Black Demon Series
Voiced by: Hibiku Yamamura (Japanese), Colleen Clinkenbeard (English)
A high-ranked possession-type demon of the Black Demon Series. He formed a contract with Yūichirō Hyakuya and became his Cursed Gear in Seraph of the End: Vampire Reign.
He also appears in Seraph of the End: Guren Ichinose: Catastrophe at Sixteen as the cursed gear of Mahiru Hīragi.
- Anime Hair: And it's fabulous.
- Big Brother Instinct: When being near-death and Sika Madu offers him the chance to not only survive but even gain immortality, Ashera only accepted it in order to find his sister Krul.
- Defeat Means Friendship: A rare inversion of the trope. Asuramaru relinquishes his power to Yuu when Yuu promises to be his friend.
- Dude Looks Like a Lady: Long and beautiful hair? Girl-like physique? Slender and elegant legs? Occasional behavior similar to a girl? And most of all a long dress? Let's just say that many fans were quite shocked when it was confirmed he was a boy. Some were even disappointed.
- Forgotten First Meeting: Chapter 79 reveals that he has met Yuu over a thousand years ago, back when he was still a human and just after losing Krul. Sika Madu bought him and kept him along with Yuu. Yuu becoming a Seraph (again, as Sika experiments on him a lot) and killed Ashera was why Sika resurrected him as a vampire. However, he's remembered this first meeting.
- Friendship Denial: He denies that he and Yuu are friends. Yuu ignores his comments.
- Hair Decorations: Wears a gold headband.
- Intrigued by Humanity: He occasionally is intrigued by Yuu's actions and way of thinking, especially his willingness to sacrifice himself for his family and friends.
- Laser-Guided Amnesia: Lost his memories after becoming a demon, but he has gained them back after chapter 79.
- Magical Barefooter: He is always barefoot.
- Not So Different: With his wielder Yuu. Like him, Ashera was fully prepared to give up his humanity just to keep his family safe.
- O.O.C. Is Serious Business: Yuu claims that he was capable of feeling his emotions, which is weird considering that demons aren't supposed to have emotions. This happened after Yuu shared a look with Krul, Asuramaru's younger sister, which might imply that he still might hold affection for her.
- Opera Gloves: He has black sleeves that separate from the dress.
- Peek-a-Bangs: His bangs cover his left eye.
- Rapunzel Hair: His hair goes beyond his feet. Ironically, like Rapunzel, he is barefoot at all times.
- The Reveal: In the Catastrophe light novels, it is revealed that Asuramaru is Ashera Tepes, Krul's brother.
- Voluntary Shapeshifting: As he exists as a mental concept, he can appear as anyone within Yuu's memories. He often takes the forms of the 12-year-old Mikaela Hyakuya but chooses his forms depending on what he believes will be best for breaking Yu's will.
- Wholesome Crossdresser
- Wistful Amnesia: In Chapter 51, after Yuu and Krul looked at each other, Yuu notices that he is feeling Asuramaru's emotions. He finds this unsettling as demons aren't supposed to have emotions.
- You Gotta Have Blue Hair: Asuramaru has dark blue hair though it appears more purple in the anime.
A high-ranked manifestation-type demon of the Black Demon Series. He formed a contract with Yoichi Saotome and became his Cursed Gear.
- Facial Markings: The left side of his face is covered with a black, curse-like mark.
- Fingerless Gloves: Wears a pair of black ones.
- Mr. Fanservice: His true form in Chapter 51 is that of a handsome young man wearing an open jacket that shows off his well-built body.
- Villain Respect: Laughs in amusement after Yoichi says that he's not as nice as he shows and plans to torture Lacus to hell and back and claims that it's why he likes Yoichi. He also seems to have an okay relationship with Yoichi that's not unlike the one between Yuu and Asuramaru.
- Voluntary Shapeshifting: In Yoichi's mind, Gekkōin often appears as Yoichi's deceased older sister, Tomoe.
Voiced by: Tomoyo Kurosawa (Japanese), Bryn Apprill (English)
A high-ranked possession-type demon of the Black Demon Series. He formed a contract with Shihō Kimizuki and became his Cursed Gear.
- Dude Looks Like a Lady: Not as much as some other demons, but he's close.
- Hair Decorations: He wears a black headband behind his horns.
- No Sense of Personal Space: In the manga, it's shown that he hugs Kimizuki closely while drinking his blood.
- Voluntary Shapeshifting: He often takes the image of Kimizuki's younger sister Mirai while battling him for control.
- You Gotta Have Blue Hair: He has as light green hair.
Voiced by: Aya Endo (Japanese), Alexis Tipton (English)
The love interest and demon weapon of Guren Ichinose. She is the main female character and plays an important role in the Seraph of the End: Guren Ichinose: Catastrophe at Sixteen light novel series.
Mahiru was from the prestigious Hīragi Family, and next in line to become head of the family; however, as a namanari, she eventually turned into a demon, and ended up being sealed within Guren's sword, becoming a cursed gear called Mahiru-no-Yo.
- The Ace: The strongest, most talented member of the Hīragi family, and before her eventual demise in the prequel, was slated to be the family's next head. Her own smarts and beauty won her over a lot of fans from her high school, but...
- Always Someone Better: She is this to Shinoa as her own successes in life left a huge shadow for Shinoa to fill in.
- Bad Dreams: Suffered from this over time thanks to the demon struggling for control inside of her. When she learned Shinoa suffered from the same thing, it drove her desire to get rid of the demon inside Shinoa by willingly participating in experiments that eventually led to the development of the Cursed Gears in the present.
- Big Sister Instinct: Towards Shinoa. Out of all the members of the Hīragi family, Shinoa was the only one she ever loved and genuinely cared for. A lot of her actions in the prequel novel, including, most especially, her act of taking Shinoa's own inner demon from her to try to give her a normal life, were not only for Guren's sake, but for her younger sister's as well.
- Bitch in Sheep's Clothing: She's revered as the Goddess of First Shibuya, but she's a morally ambiguous manipulative chessmaster whose goal is to get with Guren in any way possible. Though to be fair to her, she only became this when the demon she hosted in her body began corrupting her with its influence.
- The Chessmaster: She had a lot to do with the collapse of the world.
- Cool Big Sis: To Shinoa.
- The Corrupter: In the present, towards Guren. And in the later chapters, it's heavily implied that she plans to be one for her sister Shinoa as well.
- Cute and Psycho: Gets a bit closer to the "Psycho" end every time we see her.
- Demon of Human Origin: She was once human who became a demon as she slowly descended into madness.
- Demonic Possession: As she was born with a demon inside her, the demonic side of her gradually took more and more time in control of her body.
- Do You Want to Copulate?: Asks Guren this in chapter 4 of Catastrophe book 3.Mahiru: Please, Guren... I want you to take me. Will you sleep with me? Even if I am a monster?
- Even Evil Has Loved Ones: Despite being ruthless and quite merciless to those got in her way, she did care a lot for Guren and Shinoa when she was a human.
- Even the Girls Want Her: In the Catastrophe light novels, its mentioned that she's thought of as "beautiful" and a "goddess" by both males and females with her inspiring blushing worship in everyone. It's even lampshaded in text with the mention that "everybody seemed to adore Mahiru".
- Fatal Flaw: Her love for Guren and Shinoa eventually became her downfall.
- Fighting from the Inside: In the Catastrophe light novels, her human and demon personalities can be seen arguing and fighting for control when Mahiru-no-Yo puts Guren in danger.
- Fool for Love: Everything she's done was to be with Guren.
- Hime Cut: To signify that she's The Ojou in her family.
- I Just Want to Be Normal: In the prologue of Castrophe Volume 3, she told Shinya that sometimes she wishes that she was just an ordinary girl, and not the heiress of the Hīragi family.
- Irony: A lot of her unscrupulous actions from the prequel novels were for the sake of saving both Guren and Shinoa: from danger for the former, and from Shinoa's demon for the latter. In the present day, her now completely-possessed self is pushing for both their dooms in a huge reversal of everything the original Mahiru wanted for both of them: a happier life.
- Love Makes You Evil: Her love for both Guren and Shinoa fed her inner demon more power until it led to her being completely possessed by it. One of the first symptoms of her slow descent to evil as a result of said possession was the alarming increase of sociopathy found in her actions.
- Manipulative Bitch: Let's see: Manipulated both the Brotherhood of the Thousand Nights and her own family against each other? Check. Was one of the causes for the human vs vampire conflict in the present? Check. Is currently playing both sides of said conflict using Guren's body for as of yet unknown reasons? Check.
- Peerless Love Interest: Guren has only ever wanted her.
- Pet the Dog: She once met a young Yuu when he was being experimented on and abused by the Hyakuya Sect. Yuu kept calling himself a demon, because his parents called him that, but Mahiru is perplexed because he looks human to her.
- Protagonist Journey to Villain: The prequel novels detail her descent going from a kindhearted, if a bit ruthless, human to a sadistic, manipulative, and outright sociopathic demon.
- Psychotic Smirk: She's almost always seen smiling, but those smiles of hers in the present day are sinister enough to be this instead.
- Rapunzel Hair: Oh yeah. It passes down to her legs.
- Sailor Fuku: The only thing we ever see her in.
- Sealed Evil in a Can: She's currently the demonic host of Guren's Cursed Gear, the aptly-named Mahiru-no-Yo, and cannot act on her own unless she takes over Guren's own psyche.
- She's Got Legs: The new Guren manga defiantly shows them off.
- Shipper on Deck: A non-comedic, malicious variant. After taking a glimpse at Yuu and correctly guessing that Shinoa is growing much, much more fond of him over time, she pushes for the idea that Shinoa should pursue him, not because Mahiru personally thinks they should end up together, oh no, but because Shinoa having feelings of greed and desire would help speed up Shinoa's progress as a Namanari, turning her into a full demon.
- Single-Target Sexuality: Guren.
- Split Personality: She was a Namanari: a human halfway to becoming a demon, with two personalities.
- Split-Personality Takeover: When she became a full demon, her human personality was completely consumed by Mahiru-no-Yo.
- Split-Personality Merge: However, while it's revealed that the demon half is the dominant personality in the present, traces of the original Mahiru's personality are still in there as her love for Guren and Shinoa remain intact, albeit twisted.
- Star-Crossed Lovers: With Guren.
- Teen Genius: Considered the most talented of the Hīragi. In fact, it was revealed that she was the one who developed the Cursed Gears in the first place.
- Took a Level in Jerkass: A gradual example, and a huge sign that the demon inside of her was already wresting for control of her body within her. While originally a kindhearted individual, her inner demon slowly but surely corrupted her personality, resulting in a ton of her rather ruthless and unsavory, albeit still well-intentioned, actions throughout the prequel novel. She got even worse when she took in Shinoa's own demon from her before it was eventually returned to Shinoa again at the end of the prequel.
- The Unfettered: Became ruthless over time, reaching its peak when she mercilessly killed an innocent driver in front of a four year old child just because.
- Well-Intentioned Extremist: She joined forces with the Brotherhood of a Thousand Nights to find a way to extract Shinoa's demon from her, developing the Cursed Gear, created at the expense of the demons and ex-vampires as with the case of Asuramaru sealed there, in the process. She was partially successful, as she did extract Shinoa's demon from her, but it was all for naught when said demon was returned to her in the end anyway.
- World's Most Beautiful Woman: At least according to everyone in the school. She was even called a "Goddess".
- Yandere: She is extremely merciless towards those she considers an obstacle in her path.
- You Gotta Have Blue Hair: Mahiru has ashen (blueish-gray) hair that appears more lavender in the anime, similar to her father and her sister.
- Zettai Ryouiki: Grade A, just like her younger sister.
- If You Ever Do Anything To Hurt Him: He threatens Mahiru should she ever harm Shinya. She was unperturbed and threatened to kill Shinya if he found out what she's plotting.
- Meaningful Name: His name translates as "White Tiger" and he manifests as one.
- Nonstandard Character Design: Unlike the other human-looking demons, he's a white tiger with blue eyes. It's currently unclear if that's really his true form or not.
- Panthera Awesome: Appears as a gigantic white tiger surrounded by bright blue flames.
A high-ranked, possession-type demon of the Black Demon Series. She formed a contract with Kureto Hīragi and became his Cursed Gear.
- Affably Evil: Though she tries to make Kureto succumb to his desires like every other demon does, she speaks to him politely (calling him "anata") and is shown to be protecting him from Shikama Douji.
- Fingerless Gloves: Wears a pair of long black ones.
- Meaningful Name: Her name translates as "Thunder Demon". See Shock and Awe.
- Ms. Fanservice: She wears a rather revealing black dress complete with a Cleavage Window and an open midsection.
- Rapunzel Hair: Very long indeed.
- Scarf Of Asskicking: Wears a long black scarf.
- Shock and Awe: She is able to enshroud Kureto with streaks of electricity that can be used both offensively and defensively. She is also able to use the electricity to stimulate his muscles and increase his speed; this however tears his muscle fibers apart.
- Tsurime Eyes: She has sharp slanted eyes.
- Wild Hair: Has long unkempt hair.
A high-ranked, possession-type demon of the Black Demon Series. He formed a contract with Guren Ichinose in Seraph of the End: Guren Ichinose: Catastrophe at Sixteen and became his weapon.
A manifestation-type demon who formed a contract with Shinoa Hīragi and became her Cursed Gear. The Catastrophe novels reveal that they are the demon residing within Shinoa's body since her birth.
He is also the same demon that have possessed every head of the Hīragi Family. He reveals himself as the First Progenitor of the vampire race, who disappeared a thousand years ago.
- Affably Evil: He always speaks in a calm and serene way, thought it is up to debate whether this is genuine or not, since he keeps this demeanor even while commiting obviously cruel acts. Him being most likely the strongest being in the world, and knowing it, also means that the main reason he can act in such way is because people that can kill him are very few.
- Affectionate Nickname: Shinoa calls him "Shi-chan".
- Ambiguous Gender: In Catastrophe Volume 7, his true form is described as a slim androgynous person with horns, who appears to be around twenty-five or twenty-six years old Shinoa herself couldn't tell was male or female. In the manga, Shikama Dōji is confirmed to be male.
- Authority Equals Asskicking: He is the First Progenitor, which makes him the strongest vampire of all, and quite possibly the single strongest entity in the story.
- Bigger Bad: He is the First Progenitor, making him the creator of the vampire race. He is also have been possessing the head members of the Hiragi Family from who knows how long. In chapter 81 Saito confirms that he was the one behind the creation of of the Demon Army for his own personal uses. It gets subverted once he manages to take cover Shinoa Hiragi's body and takes action.
- Big-Bad Ensemble: He is one of the main villains of the story, alongside Saito.
- Bishōnen: He's a very pretty demon.
- The Corrupter: He tried to make Shinoa desire Yuu so he can take over her body and possess her. It worked.
- Curb-Stomp Battle: Ferid and Crowley attempt to kill him while he is taking over Shinoa's body, but he manages to deflect their attacks while lying down. The rest of the battle is not shown but later Ferid appears and tells Guren, Shinya, Kureto and Mika to run.
- Deal with the Devil: After Shinoa refuses to let him possess her, he starts offering several stuff: first the chance for her to see his memories, then the chance to save her brother Kureto, then the chance to turn Mika back into a human and then, finally, the chance to return Yuu's humanity into him. Shinoa has every reason to believe that all these offers are lies.
- Demonic Possession: While he was also in Shinoa's scythe, in truth, he was also residing in Shinoa's body, waiting for the day Shinoa succumbed to desire so he could take possession of her. Unlike Mahiru-no-Yo though, he was pretty patient about it since Shinoa's lack of desire is something that kind of impresses him.
- As mentioned above, he has possessed every head of the Hīragi Family.
- He is the only known demon to possess multiple people at one time thus far in the series. He possessed Tenri at the same time he was with Shinoa and Mahiru and was possessing Kureto at the same time he was possessing Shinoa.
- Dissonant Serenity: Due to him being pretty much immortal and near invincible, Shikama is unperturbed by threats and the killing of his former host
- Divinely Appearing Demons: Looks very much like an angel with three pairs of white feathered wings protruding from his back. Adding to that, he has two white wings curved around the top of his head and two smaller wings hanging behind his ears.
- The Dreaded: Everyone who knows him, both humans and vampires, are terrified of this guy. Even vampires, that are known for both arrogant and fearless, refer him as a monster. Considering who he is, it is no wonder.
- Dude Looks Like a Lady: Very much so.
- Friendly Enemy: He always acts friendly towards Shinoa. Given that he is constantly trying to possess her, it is up to debate whether he is actually being genuine or not.
- Given Name Reveal: In Chapter 68, his name as a vampire was revealed to be Sika Madu.
- Good Wings, Evil Wings: He has three sets of angelic wings. He does realize the irony of having them despite his unholy nature.
- Hypocrite: He calls Shinoa callous for having no interest in saving her brother Kureto, who has always been anything but nice to her, when a thousand of years ago he clearly had no trouble in separating Ashera Tepes from his sister Krul and turning him into a demon, making him lose all the memories of his beloved sister.
- Lack of Empathy: A trait that all vampires inherited from him, though his is shown in a much darker way. While vampires don't really care about humans in general and regard them as mere livestock they don't go on their way to kill humans without being actually necessary. Shikama, on the other hand, has killed plenty of humans, children to be more precise, for his experiments for 600 years nonstop. Even those that succeeded in his experiments didn't get that much appreciation and he eventually abandoned them all, except Ashera, to further his own goals.
- Long-Haired Pretty Boy: An effeminate looking demon with waist length hair.
- Man in White: He wears a white or possibly a light colored dress that further emphasizes his angelic appearance.
- Magical Barefooter: He is barefoot.
- Monster Progenitor: Before becoming a demon, he was the First Progenitor of the vampires.
- Nigh-Invulnerability: He has stated that pretty much nothing, not even a Seraph, can kill him.
- Parental Abandonment: Aside from Ashera Tepes, he was quite neglectful towards the other vampires, and eventually abandoned them.
- Physical God: Still not proven, but taking into account that others either call him 'monster' or 'god', he is the closest of being one in the story.
- Pint-Sized Powerhouse: He takes over Shinoa's body, a petite girl, and given the Curb-Stomp Battle he gave to Ferid and Crowley the body clearly didn't restrain his power.
- Power Gives You Wings
- Sinister Scythe: After possessing Shinoa's body, he uses the scythe that she used.
- Who Wants to Live Forever?: Near immortality has Shikama Dōji wanting to die. He even says to Kureto that if the latter manages to kill him, he'll be extremely grateful of that as being unable to die is painful.
- Would Hurt a Child:
- Centuries ago, he constantly bought children as slaves for his experiments, and until he bought Urd, Saito and Ashera all of said children died. This fact by itself is already quite disturbing, but reaches Nightmare Fuel when he says that he has been doing this for 600 years, leaving up to the imagination, and horror, just how many children died.
- The reason why Yuu tends to forget everything after just a few day is because whenever the Seraph in him goes crazy and starts destroying things or killing people, Sika Madu will kill him and resurrect him.
- Undying Loyalty: Sort of, to Shinoa. After his brief tenure of being Mahiru's own Cursed Gear for a while, Shi asks that they be returned to Shinoa since "they're bonded together". Subverted, that he doesn't really care about Shinoa, only wanting to possess her body.
A demon who is summoned by Kureto Hīragi from Mirai Kimizuki's Fifth Trumpet.