Voiced by: Daisuke NamikawaAkutabe is a detective that specializes in using demons. He is very knowledgeable in the occult, and uses this knowledge to overpower the demons, even enabling him to block a powered up "divulgence" spell from Beelzebub. He is Sakuma's employer as well as a mentor. He will summon demons to do his bidding and will often mistreat them if they annoy him or mess up their assignments. He is shown to be cruel and rather sadistic, causing even demons to be afraid of him.
- Aura Vision: A very dark one.
- Bad Boss: Just look how he treats the demons! (Exception for Sakuma).
- Badass Bookworm: He's always reading something, anything, and when he gets mad it leads to a Throw the Book at Them moment.
- Bastard Boyfriend: Well, Undine does think she's in a relationship with him...
- Brutal Honesty: Gives one hell of a speech to Azazel during his Despair Event Horizon, and the sad thing is (Or not) he is exactly right in what he says.
- Brainy Brunette: One of the things that makes him so powerful is his vast knowledge of the occult.
- Cold-Blooded Torture: As punishment for the demons.
- Death Glare: Always.
- Dark Secret: God help you if he suspects that you know it...
- Dynamic Entry: Performs one at the end of chapter 63◊.
- Evil Mentor: To Sakuma.
- Evil Sounds Deep: His voice is usually a deep one, but he temporarily changes to a more kind and innocent tone when trying to convince Undine to sign the contract.
- Face Framed in Shadow: Except that it's perpetual.
- Glowing Eyes of Doom: Whenever he's pissed off, especially if the demons mess up his assignments. Often combined with Red Eyes, Take Warning.
- Hellish Pupils: Even more in the manga.
- Heroic Comedic Sociopath
- Iconic Outfit: In-Universe. Almost everyone recognizes him because of the hairstyle and the suit.
- Even in the second OVA Azazel pissed his pants of the sight of a guy with spiky black hair and a black business suit.
- Impaled with Extreme Prejudice: He impales Azazel, Beelzebub and Salamander only with Sakuma's umbrella.
- Idiot Hair: From all the silly characters on the series, it is him who has an ahoge.
- Jerkass: With nearly everyone he meets. He seems to have a soft spot for Sakuma though...
- Messy Hair
- Nominal Hero: Or Villain Protagonist?
- No-Sell: He can casually deflect Beelzebub's ultimate attack one handed.
- Not So Stoic: When he finds the landlord lady stole one of his grimoires. He wasn't happy.
- Also when Moloch's younger brother found out something about him that he really wanted to keep secret. He really wasn't happy, to the point where he gave Moloch a heart attack.
- Occult Detective
- One-Hit KO: Most of his punishments towards the demons.
- Only One Name: His first name, if he even has one, has not been disclosed yet.
- Only Sane Employer
- Perpetual Frowner
- Power Fist: Occasionally he will use his fist for whatever rage he might have. And somehow his right hand always seems to have a dark aura...
- Reflectionless Useless Eyes: Which serves to show his cruel personality.
- Ship Tease: With Sakuma, even from the very first chapter.
- At one point Koutarou asks Azazel if he knows Akutabe's taste in porn, and Azazel says he does... and he picks a bondage video featuring a Sakuma-lookalike.
- Slasher Smile: Basically the only smile he ever shows. An even creepier one in the manga.
- The Snark Knight: He doesn't seem to show affection to anyone, and it's very implied he hates most people.
- The Stoic: He has two basic facial expressions: stoic and pissed off.
- Straight Man
- Surrounded by Idiots: He seems to be the most competent character in the series.
- Throw the Book at Them: To every supernatural being who dares to piss him off. It's enough to make their life flash before their eyes.
- Played with because if a demon touches his own grimoire, it leads to a painful torture.
- Tsundere: Kotaro tries to convince Undine that he's this.
- Torture Technician: The demon summoning room is filled with tons of medieval torture devices. And he knows how to use them.
- Unusual Eyebrows: He apparently doesn't have any eyebrows.
- What the Hell, Hero?: Talks down and coldly brings Azazel down to earth by telling him how can this guy, a demon, be such a little bitch, whining about everything and expecting kindness and gratitude from humans, and relying on their praise. It's possibly the nicest he's been to Azazel throughout the entire series so far.
- Would Hit a Girl: He kicks Undine off him with absolutely no regret. He also has no problem with piercing Sakuma's finger, causing gushing blood.
Rinko Sakuma (佐隈リん子)
Voiced by: Rina SatoRinko Sakuma is a university student and part-time assistant of Akutabe. Young and naive, she is just starting to learn about the power of demons. She is bound in a contract with the demon Azazel.
- Adaptation Dye-Job: Her eyes are dark blue in the anime, while in the manga they are dark green.
- The Apprentice: To Akutabe.
- Badass Bookworm: She can cast a spell which can make Azazel explode in a million pieces, causing Beelzebub to be terrified of what she has become.
- Berserk Button: Sakuma has a strong sense of justice. Azazel learns this the bad way.
- Blind Without 'Em: Maybe it's better this way. When Undine cures her miopia temporarily, she appears to see more than one'd like her to.
- Brainy Brunette
- Baleful Polymorph: She almost got turned to a cow by Moloch and later also to a panda by Behemoth.
- Then into a granny by Undine.
- Butt-Monkey: Whatever plan the demons come with, she always gets the worst part.
- Character Development: She starts as a naive, innocent girl. As the series progresses and she learns more about the demons, she becomes considerably darker, but still keeping her nice personality.
- Cosplay Otaku Girl: She's forced to cosplay Strawberry Warrior to get some notes.
- Cute Secretary
- Dark and Troubled Past: Played for Laughs only. When she was a kid, she used to get bullied by a group of other kids, but when a pedophile started molesting her, the same bullies got rid of him.
- Dude Magnet: Implied. You could count the times she gets harassed by the demons (and some humans) with more than one hand. At some point Azazel even tries to kiss her.◊
- Identical Stranger: A soldier mistook her for a woman he fell in love with while he was at war. They look exactly the same,◊ the only difference being the clothes.
- Karma Houdini: No matter how much of a disaster or stupidity she may commit, Akutabe never seems to get angry at her neither punishes her. While he will at least punch someone for messing up something, he never lays a finger on her. Some of the demons even lampshades this.
- Hard-Drinking Party Girl: She gets drunk easily and even says that "she can't refuse a drink".
- High-Pressure Blood: When Akutabe cut her finger to make a demon contract.
- Meganekko: Undine thinks she uses this to attract men.
- Akutabe-san, what have I done?: Invokes this in spades once she realizes Incubus's true intentions after Kiyoko confesses to her rape.
- Oh, Crap!: When Azazel catches Kiyoko having sex with Incubus, and then after that when Kiyoko talks about the plot against Azazel.
- Only Sane Woman
- Scary Shiny Glasses: More and more as the series progresses.
- She Cleans Up Nicely: She looks a lot cuter without her glasses, or in feminine outfits.
- Ship Tease: With Akutabe.
- Throw the Book at Them: In the second season, she smashes Azazel so hard, he ends getting cooked by the earth's core.
- Unlimited Wardrobe: Unlike Akutabe, she gets to wear something different in every volume/episode.
Atsushi Azazel (アザゼル)
Voiced by: Masaya OnosakaA dog-like demon who is the title character. He is a pervert who gets never-ending enjoyment in sexually harassing others, especially Sakuma. He is also deathly afraid of Akutabe, who tends to abuse him when he gets out of line or fails to accomplish a goal. His ability is called Lewdness, which gives him the ability to incite lust. His powers range from making people attractive, unattractive, and even cause impotence. When Akutabe ended their contract, he became contracted with Sakuma much to her chagrin.
- Alliterative Name
- Animal Motif: Technically he's a satyr, but in the human world he usually gets mistaken for a dog (despite the presence of horns, hooves and spiky tail).
- Domestic Abuse: Gets abused by his girlfriend Kiyoko.
- Evil Redhead: Well, he's a demon.
- Excalibur: Appropriately, his trident is called Sexcalibur.
- Dark-Skinned Redhead: In his true form.
- The Idiot from Osaka
- Japanese Pronouns: Washi.
- Lovable Sex Maniac
- Lust: The personification of.
- The Nicknamer
- No Sense of Personal Space: Intentionally towards women.
- Red Oni, Blue Oni: Red to Beelzebub's blue.
- Vitriolic Best Buds: With Beelzebub.
- Walking Shirtless Scene: His real form◊. He wears no shirt and his only pants seems to be his own hair. It also applies in his form in the human world.
- What The Hell, Azazel? When he returns to the human world after a week of not answering any summons or calls, his mother and Kiyoko hitch a ride... only to have him find out that he's been replaced by Incubus, a demon with similar abilities as Azazel and who isn't as useless. However, Azazel ruins his opportunity to improve and show that he's changed, and pretty much screws up whatever task is given to him. Incubus does his job for him and is presented a proper sacrifice. Azazel, however... is given a cube of fat. Rinko tells the visitors that he's been having that sacrifice for a long time, making it succinctly clear that Akutabe's offices are done with him and will not have any of his shit, if their treatment of Incubus didn't make it anymore clear. His mother and Kiyoko are horrified and pretty much disown him when he eats it in absolute shame. He even sheds a tear. And he had every second of it coming.
Yuichi Beelzebub (ベルゼブブ)
Voiced by: Hiroshi KamiyaA childhood friend of Azazel who is a part of an elite family of demons. Despite appearing to be a bird, he is actually a fly demon who eats feces much to the disgust of those around him. He also has an ability called Divulgence which gives him the power to make others reveal their hidden selves ranging from revealing the side of them they don't want people to see, to forced defecation. He can also use goat dung as a doping drug, making his attacks considerably more powerful. Azazel's nickname for him is Bēyan (べーやん).
- Affably Evil: Arguably the least outwardly hostile and most helpful of all the demons to Sakuma and Akutabe. Though that's really not saying much.
- Bishōnen: His humanoid form◊. It's even a plot point.
- Black Bead Eyes
- Big Fancy House: His mansion.◊
- Conspicuous Trenchcoat: He wears one when following Sakuma in her new habits.
- Deadly Gas: His breath in his monstrous form.
- Everything's Better with Penguins
- Animal Motif: At first, one would think he's a bird. He's actually a fly.
- Japanese Pronouns: Watashi.
- Red Oni, Blue Oni: The blue to Azazel's red.
- Rich People: Very implied. He has a butler to serve him curry.
- The Smart Guy: He's the one who explains most of the things to Sakuma about the demon world and he's the one who comes up with most strategies. He also got higher grades than Azazel in school.
- Toothy Bird: Or at least he looks like a bird.
- Trademark Favorite Food: Aside from his... peculiar tastes, he really loves curry.
- Vitriolic Best Buds: With Azazel.
Kimitake Salamander (サラマンダー)
Voiced by: Kazuya NakaiSalamander is a red lizard-like demon who was originally summoned for personal, selfish reasons, but because the summoner was an amateur, Salamander ended up possessing him. Salamander has an ability called Revolution which makes people believe their own words when they say things they don't truly believe. He always carries a Katana that is strapped to his waist. Azazel's nickname for him is Manda-han (マンダはん).
- Animal Motifs: Well, he's a lizard.
- Japanese Pronouns: Sessha.
- Large Ham
- More Than Mind Control: His ability, Revolution.
- Named After Somebody Famous: Yukio Mishima, specifically.
- No Celebrities Were Harmed: With his harsh misogyny, obsession with "traditional values" and his fundoshi-and-katana outfit, he's a caricature of Yukio Mishima.
- Too Kinky to Torture: He's a masochist.
- Straw Misogynist: To the point where the director of the anime decided to enlist Kazuya Nakai in hopes of making him even a little bit popular with female viewers. The plan worked.
Megumi Undine (アンダイン)
Voiced by: Yuu KobayashiUndine is a mermaid demon, with the ability to take on human form. She has fallen in love with Akutabe much to his chagrin. Her ability is Jealousy by which she can change the world around herself. When she is happy, these curses are undone.
- Christmas Cake: According to her parents, she's in her mid 30's.
- Face Framed in Shadow: Her form in the demon world. You can only see one eye.
- Godiva Hair: In her original form.
- Good Smoking, Evil Smoking
- Green-Eyed Monster: She is the personification of envy...
- Purple Eyes
- Reality Warper: She is able to change anything she is jealous of, be it an individual or an entire school with all its students and teachers.
Yoshinobu Moloch (モロク)
Voiced by: Tessho GendaA bull like demon under Akutabe's control. According to Azazel and Beelzebub, he is the most violent demon in Hell and both are evidently scared of him, especially when he is angered. Akutabe praises him as a demon on a higher league then his other demons and explained that he has the ability called Violence though what it does is unknown. He was apparently killed when Sariel took his grimoire to heaven. His nickname is Mossan (モッさん).
- Animal Motif: A bull.
- Black Bead Eyes
- Hair-Trigger Temper
- Killed Off for Real: When his grimoire was stolen by an angel. He's replaced by his Backup Twin in season 2.
- Murder Is the Best Solution: He repeatedly suggests killing Akutabe. And then his brother tries,◊ but it goes horribly wrong.◊
- Red Eyes, Take Warning: He's the most violent demon in hell, Azazel and Beelzebub are deathly scared of him.
- We Hardly Knew Ye: Little is shown about him in the anime...
Voiced by: Takehito KoyasuOne of the most powerful demons, he is the Lucifer of Biblical legend (although it's not quite clear if he really is a fallen angel or not). His ability is manipulating time, enabling him to bring back something that was destroyed or make a person older or younger at will. His sacrifice is "weed."
- Animal Motif: A koala.◊
- Breath Weapon: Is able to shoot some sort of destructive beam out of his mouth.
- Gratuitous English: His tattoo, "God /bless/ fuck your ass" (which looks suspiciously as if it had been originally "God bless you" before he crossed out "bless" and added the rest).
- Hellish Pupils
- Hell-Bent for Leather: The complete set.◊
- It's All About Me: Well, he is the personification of Pride.
- Fangs Are Evil
- Japanese Pronouns: Ore and ore-sama.
- Power Tattoo: The snake that goes from his arm to his chest (holding an apple).
- Rock Me, Asmodeus!: He has a rock star theme going on, complete with an orbital ego, plus tattoos, leather pants and accessories. He also enjoys playing the guitar, which leads to...
- Rockers Smash Guitars: Ironically, he's not the one who smashes the guitar, but Akutabe.◊
- Scaled Up: His true form is a huge black dragon.
- Sunglasses at Night
- Tall, White-haired and Handsome: his humanoid form.
- Time Master: His main ability.
- Unusual Eyebrows: Like Akutabe, he has none.
Kotaro Dochin (堂珍 光太郎)
Voiced by: Ryoko ShiraishiA boy who is the grandson of an acquaintance of Akutabe. His overall personality is parallel to Azazel, albeit a lot more bratty and verbally abusive. Examples of this includes sexually harrassing Sakuma on their first meeting and picks a fight with Azazel. He is contracted with Gusion.
- A Boy And His Memory Eating Demon: No matter who's around, he's always with Gushion.
- Anime Hair
- Bratty Half-Pint
- Deliberately Cute Child: Tries to pull it off from time to time to manipulate people. Sometimes it even works.
- Enfant Terrible
- Mouthy Kid
- The Peeping Tom
- The Prankster: He gives Akutabe a fake grimoire in his introductory chapter, between others.
- Red Oni, Blue Oni: The red to Osamu's blue.
Voiced by: Takashi Taniguchi (First season), Jurota Kosugi (Second Season)Ruler of Heaven and Angels. He has told angels to go down and fetch grimoires so that demons can be killed, properly. Bit of an odd guy, with a juvenile sense of humour and mastery of Impossible Shadow Puppets. Really doesn't like angels who fail him.
- Berserk Button: Angels who don't bring back grimoires within the time limit.
- Cloudcuckoolander: Doesn't really seem all there.
- The Faceless: Just appears as a shadow all the time.
- For the Lulz: Just wants to have fun and make jokes, even if it's at the cost of others misfortune.
- The Gods Must Be Lazy: Would it really kill him to allow angels to interfere a bit in human lives just as demons do?
- Impossible Shadow Puppets: He does it to himself since he is represented as just a shadow. He makes a realistic shadow penis, but then just turns his hands into jiggling breasts and puts them on his face, all Played for Laughs.
- Red Eyes, Take Warning: When angry, he gets a pair of expressive eyes and a symbol on his forehead.
- Stop Worshipping Me: Seems to get frustrated at how the angels do nothing but fawn over him and agree all the time. He does he concedes it a great disrespect when angels fail him though.
- Toilet Humour: Mimes defecating with shadow puppets, although whether this is because that's his thing or really what Zeruel liked as comedy is unclear.