The eponymous compulsive gambler, a New Transfer Student at Hyakkaou Private Academy who quickly throws the established order into chaos with her habits. Gambling is Serious Business to her, but not in the way one might expect—she's truly unpredictable, not caring whether she wins or loses so long as she can enjoy the insanity of her and her opponent putting everything on the line on a truly uncertain outcome. Her current goal is having a match with Kirari Momobami, though of course she isn't going to turn down challenges from the rest of the Student Council along the way...
- Almighty Janitor: Even as a House Pet, Yumeko is terrifying, to the point it seems that many people prefer to not mess with her. She is especially a problem to the Student Council, exactly because she has such low rank in her school, since she can now force Official Matches on them and they can't refuse, and so she becomes a huge looming shadow over the Council.
- Aloof Dark-Haired Girl: An unintentional example. When not gambling, Yumeko is polite to everyone—she never engages in gossip, apologizes to a group of girls who tried to bully her for being dissuaded with her Cat Girl antics, pays off Suzui's debts with no strings attached, and even seems genuinely concerned when Mary's desk was vandalized on her first day as house pet. But her personality when gambling creeps people out enough that Suzui and Mary are pretty much her only friends at school.
- Ambiguously Bi: She has a fair amount of Ship Tease with Suzui, but she also has a bad case of No Sense of Personal Space towards both her friends and her opponents, most of whom are female. She also tends to be rather touchy-feely with Mary. An omake in volume 3 shows Ikishima constantly pestering Yumeko while she is clinging to Marys arm not unlike a lover would. At one point it even seems that Yumeko was trying to kiss her! (Most likely on the cheek, but even that isnt very common between friends in Japan). But Yumeko clearly prefers gambling over sex, so this kind of behavior may really not mean anything to her.
- Animal Motifs: Her schoolmates compare her to a snake, and she's even drawn with the sideways pupils seen on multiple varieties of snakes when she's going especially nuts for gambling; Kirari later refers to her as the "snake that has slithered into their paradise". Furthermore, the 蛇/"Ja" character in 蛇喰/"Jabami" can be read as "snake".
- Batman Gambit: She regularly analyzes other players' habits and schemes, and sets them up to lose if they continue through with their normal actions. However, if they abandon their schemes, they can have a shot at actually defeating her, which only adds to her excitement.
- Berserk Button: While the threats of mutilation, slavery, rape, and even death seemingly have no effect on Jabami, ruining her ability to enjoy a game of chance will drive her into an instant rage.
- It's the reason why, so far, Ikishima, who rigs games to lose 100% of time, seems to be the only person Yumeko actually hates. So much so that, for a time, she ignores her entirely and pretends she doesn't even exist, even when others are speaking to her.Yumeko: Do you even understand what you've done? [...] It was a 2-in-1 chance. It all came down to a coin flip. It was like a miracle created by God! With a single, perfect choice waiting for us at the end! You took that final moment and trampled all over it.
- She later delivers a similar anger towards Yumemite when she declares that she has given up the gamble after being overwhelmed by Warakubami, essentially breaking her promise with Yumeko of letting her see Yumemite dominating Warakubami. That's why she decided to play solo in the Soxiante-Trois game
- It's the reason why, so far, Ikishima, who rigs games to lose 100% of time, seems to be the only person Yumeko actually hates. So much so that, for a time, she ignores her entirely and pretends she doesn't even exist, even when others are speaking to her.
- Better Than Sex: She has near-orgasmic reactions when just thinking about gambling, wrapping her arms around various parts of her body, blushing, and even having little trails of drool starting to drip out of her mouth. Thankfully downplayed in the live-action adaptation.
- Blue and Orange Morality: Jabami's entire morality system seems to be based around gambling, with greater risk equated to good and less to bad. While she can replicate "normal" behavior and morality as needed, they have seemingly no actual meaning to her.
- She sees cheating as just a way to make games more "interesting", and only exposes certain cheaters not because what they were doing is "wrong", but because they were using it to make things more predictable (and thus boring). For instance, she lets Saotome's ¥8.8 million debt to her slide and tips Suzui ¥5 million on her first day for putting together an interesting con. And in the debt recollection arc, she actually tells her opponents how they can cheat better, just to make their card game an actual challenge.
- Similarly, people who aren't risking something important, and making Jabami do the same, disgust her. She finds Sumeragi "boring" for refusing to bet something that would actually affect her life, like her nails. She similarly pouts at Nishinotouin for cheating to assure she'll always end up with net positive gains. And she actively hates Ikishima for rigging games so she can lose and feed her Death Seeker tendencies, as it means Jabami can't engage in equal levels of risk with her.
- Brutal Honesty: Usually Yumeko speaks in a very sweet and polite manner, but she tends to drop it when an opponent has done something to draw her ire, as seen when she calls Yuriko a piece of shit for manipulating Mary and relying on her fortune to avoid the consequences of her risky trick.
- Buxom Is Better: The bustiest girl in the cast, which the anime's opening and ending draw special attention to. Averted in the live-action adaptation.
- Catchphrase: Is fond of using the phrase "shall we gamble?" note right when she puts the finishing touches on her latest Batman Gambit. In Japanese, she's doing a Title Drop: Kakegurui mashou!
- Cute and Psycho: Watch her acting like a sweet Yamato Nadeshiko one minute. Then watch her turn into a gambling monster the next.
- Disqualification-Induced Victory: At the end of the Finger Guillotine game, Erimi withdraws her finger at the last moment when the guillotine finally came down (though an iron bar protected their fingers); however, because it did went down after Midari cut the last two strings simultaneously, the latter gets disqualified, thus leaving Yumeko the winner by default. Needless to say, she is absolutely livid at Midari for letting her selfish need for pain get in the way of a good game of chance yet again.
- Dissonant Serenity: After being reduced to housepet status, her would-be bullies in class are too freaked out by Jabami's disturbingly cheerful attitude about it to even remain in the same room as her.
- Dull Eyes of Unhappiness: Instead of a vivid red, her eyes turn to a lifeless pure black after games she deems boring. This holds especially true with Ikishima, whose greedy sadomasochist "selfishness" angers her to no end.
- Eerie Pale-Skinned Brunette: She normally comes across and sweet and polite, but once her true self comes out, she transforms into this.
- Even Evil Has Loved Ones: She's more insane and unpredictable than evil, but Yumeko has a sister which she's taken well care of with her own funds, and genuinely considers Suzui (and later Mary) a friend, even inviting him to hang out at a sweets buffet. Implying Suzui is a slave and not a friend to her is one of the few ways to tick her off that doesn't involve her risk addiction Blue and Orange Morality. That said, it's also pretty clear that her idea of friendship is still skewed in certain ways, as seen in how she goads Sumeragi into betting her very life during the gamble with Manyuda.
- Even the Girls Want Her: Yumeko has a lot of open sexual tension with other girls, and Ikishima is directly in love with her.
- Everyone Has Standards: As surreal as her morality towards gambling is, she especially finds Ikishima disgusting because the latter rigs her games so she can die.
- Family Theme Naming: Her last name, especially the second character of her name, "bami", indicates that she is somehow related to the Hundred Devouring Families where Kirari and Ririka hail from.
- Foil: Though they're both crazy and skilled gamblers, she shares some opposing differences with Mary.
- Yumeko obviously comes from a wealthy family, considering she brought in 10 million yen in cash on her first day of school and is related to a powerful clan that Kirari is also a part of; Mary is a Scholarship Student, thus not from a rich family.
- Yumeko gambles for thrills; Mary gambles to stay on top of the dog-eat-dog hierarchy of Hyakkaou.
- When not gambling, Yumeko is polite and friendly to others; Mary is an abrasive Tsundere.
- Yumeko deliberately stays as a house pet, seeing it as an opportunity to gamble with the student council president; Mary resents her house pet status and tries to get out of it as soon as she can.
- Even their appearances are different, with Yumeko having black hair styled in a Hime Cut with brown eyes (red when gambling) and Mary having blonde hair that she keeps tied up and gold eyes.
- The Gambling Addict: It's all in the title. Jabami likes to expose cheaters not For Great Justice or to make herself rich, but because she enjoys gambling the worse her initial odds are. Knowing she'll automatically win or lose is just too boring for her. Kirari lampshades it after she defeats Manyuuda, saying if she really wanted to force Jabami to leave the school, all she'd have to to do is ban her from gambling.
- Graceful Loser: She takes her loss to Nishinotouin (due to Kirari's interference) and subsequent demotion to house pet scarily well, telling Suzui how amazing Kirari was for apparently customizing the entire wing of the school where the match took place, and now she badly wants a match with her. Conversely, she also believes in being a humble victor, even telling Sumeragi to go easy on Manyuuda after they won against him.
- Hannibal Lecture: Likes lecturing her opponents about the exact nature of their cons, and why trying to bring order out of the chaos that is gambling is not only worthless but pointless, right before she utterly crushes their schemes.
- Happiness in Slavery: Discussed by Mary and the Student Council at various points in the story. Jabami has the money to easily pay off her debt to Nishinotouin, but willingly abstained from doing so, going so far as to give up an opportunity to clear her debt in favor of Mary's, just so she can take advantage of her right to mandatory public matches to challenge anyone—including Kirari herself—to sate her addiction.
- Hustling the Mark: Jabami at first appears to be a quiet, naive Yamato Nadeshiko-type, making her seem like an easy mark for various cheaters at the school to get money or servitude from. It's only once they actually start playing that Jabami's sociopathic gambling addict tendencies surface, and she shows herself to be an expert at reading others and seeing through schemes.
- Iconic Item: While her school uniform is very standard, Jabami wears a silver ring on her left thumb.
- Insult Backfire: Jabami doesn't mind being called out for her insane gambits, as she believes insanity is the very essence of gambling. Even after being reduced to house pet after her loss to Nishinotouin due to Kirari's interference, she is so unnaturally enthusiastic playing a Cat Girl that her bullies don't know what to make of her and are creeped out.
- Invincible Hero: Yumeko could be this if she wasn't purposefully working to subvert it. She always figures out her opponents' cheats and never breaks a sweat in any match, and Terano comments that Yumeko would have already defeated the apparent Big Bad of the series if she really wanted to, implying Yumeko's skill and ability is way above everyone else. One defining aspect of Yumeko's personality however is that she's addicted to risk, thus she always leaves open the possibility of her own defeat. Therefore despite already figuring out the opponent's cheat and how to beat it, in the cases where there isn't at least some luck involved in the final round that could allow her to lose, Yumeko will warn her opponent first to give them one last chance to defeat her before being Hoist by Their Own Petard.
- It Amused Me: Discussed. Jabami readily admits that from a pure financial perspective, gambling is something no sane person should willingly engage in. As far as she's concerned, it's only the entertainment derived from this "insanity" that has any real worth.
- Lack of Empathy: When meeting with Manyuuda again in the Greater Good Game and faced with an Armor-Piercing Question on how she gleefully ruin people's lives with her games like she did with him, she admits that she does feel guilt...of not feeling guilty at all.
- Laughing Mad: Upon hearing from Suzui the entire school gambles, she starts chuckling to herself.
- The Magic Poker Equation: Jabami only gets a winning hand in her match with Mary after she bets ¥10 million. She even lampshades it afterwards, saying she had awfully "good luck". This is taken Up to Eleven against Manyuuda, winning with a trio of jacks against his trio of eights, after she had discarded a pair of queens.
- Manic Pixie Dream Girl: Deconstructed. After transferring to Hyakkaou, she saves Suzui from his debts and becomes Fire-Forged Friends with him and Mary to a degree. That said, Jabami loves gambling much more, and both Suzui and Mary cannot help but get sucked into her antics. Later Suzui realizes that he's falling in love with her, but his thoughts describe how a large part of it stems from watching the insane spectacles she creates. Sumeragi similarly freaks out at the end of the idol arc when she remembers Jabami's idea of "friendship" is talking Sumeragi into putting her entire fortune and personal freedom on the line.
- Meaningful Name: Jabami Yumeko can be read as "snake-devouring dream girl", referring both to her penchant for taking down cheaters and her general detachment from reality.
- Money Is Not Power: In the debt recollection day, she willingly foregoes the chance to clear her debt to Nishinotouin just to see a fellow "house pet" stand for herself, as money is more or less meaningless to her.
- Mysterious Past: She brings ¥10 million with her on her first day of school, and later the Student Council discovers that despite living alone (both her parents are dead, and her only other relative, an older sister, is hospitalized), she'd apparently has no problem paying off her debts, but nobody knows where she gets the money from (and she sure won't tell). Now that Kirari's extended family has come onto the scene, it appears that the Jabami family is actually distantly related to them, and even said family doesn't have a lot of information about her.
- New Transfer Student: The story begins with her transferring into the second year of Hyakkaou's high-school division midway through the school year.
- Nightmare Fetishist: Practically has an orgasm while describing to Sumeragi how they'd both suffer from ripping off their nails, for starters. Later, she gets really into her role as a house pet, and even point-blank asks a group of boys who demand she strip if they plan on doing anything violent to her, deciding that they "aren't her type" when they say no.
- No Sense of Personal Space: Played for Laughs — Jabami can get pretty grabby, especially whenever she's around Mary or Suzui.
- Not So Above It All: Can be just as underhanded as her opponents if it's for the sake of gambling, such as when she plants a recording device to tape Yumetime ranting about her life as an Idol Singer so they can both enjoy the thrill of putting their entire livelihoods on the line. Though from Jabami's point of view, cheating is just another way to make games more chaotic and risky, like adding a new game rule.
- O.O.C. Is Serious Business: Rather than being aroused like she normally does after every game, she was absolutely furious at Ikishima for not only deliberately rigging her games so she can lose and thus be killed, but also for insinuating that she was just using Suzui as a pawn.
- Photographic Memory: Shown to have a phenomenal memory, being able to memorize the minor sets of defects on the back of 52 out of 104 different playing cards and their corresponding faces in a few minutes. During her gamble against Ikishima, Suzui (who is their dealer) uses this trait in order to give her the advantage. After her match with Yumemite, she's also able to use it to completely reproduce one of Yumemite's several minute long complicated dance routines for an impromptu duet.
- Professional Gambler: Jabami shows up with at least ¥10 million of her previous winnings in her bag during her first day at school. She also has no problem letting Saotome's ¥8.8 million debt to her slide since she "had fun", and further decides to give Suzui a ¥5 million tip for letting her enjoy an interesting game. The Student Council also later discovers that she has enough money to easily pay back a ¥310 million debt to Nishinotouin, but willingly abstains from doing so in order to have more excuses to gamble.
- Raven Hair, Ivory Skin: Most of the time, it's easy to take her for a run-of-the-mill Yamato Nadeshiko or The Ojou. However...
- Red Eyes, Take Warning: They're normally a very amber-y brown, but when a game starts, they're depicted as bright red to emphasize her madness.
- Secretly Wealthy: Subverted. Yumeko brings in 10 million yen on her first day in school and the student council discovers that she pays for her sister's hospital treatment. She even hints that she could just pay off any debt she can get in school but chooses not to because that would be boring. Therefore, the secret is whether or not she's wealthy, but how wealthy she is. Now that Kirari's extended family has come onto the scene, it appears that the Jabami family is actually distantly related to them, which may help explain why she is so rich.
- Sherlock Scan: Jabami is extremely good at noticing details and applying deductive reasoning. For instance, in her game with Sumeragi she notices and then memorizes minor sets of defects on the back of 52 out of 104 different playing cards and their corresponding faces in a few minutes. In her game with Nishinotouin, she figures out exactly how her opponent is using magnetic piercings in the dealers' hands to cheat, after simply seeing identical piercings on two of Nishinotouin's club members and three rounds of their custom "Life or Death" game.
- To the Pain: When trying to coerce Sumeragi into a round three, she suggests they each bet having all their fingernails and toenails ripped out if they lose, and starts going into detail over how she's heard it hurts even more afterwards and will cause the affected digit to bleed if even the slightest pressure is applied. While Jabami finds describing this level of risk... deeply satisfying, Sumeragi is reduced to tears.
- Wild Card: It's brought up time and time again that she almost never acts rationally and is nearly impossible to predict. Probably the best example of this is when she uses her "house pet" privilege of declaring a public match — with anyone, that can't be refused — with Manyuuda, when everyone had been expecting she was saving it for Kirari instead, because he was refusing to gamble with her right then and there. And Manyuda had, up until that point, prided himself on being able to account for her unpredictability!.
- Yamato Nadeshiko: When not gambling, Jabami appears to be a very demure and soft-spoken Japanese beauty, with long, straight black hair and a very conservative version of the school's Nonuniform Uniform.
The girl in charge of Yumeko's class when she transfers in, and the first casualty of her gambling skills. Forced into house pet status after attempting to make up for her losses by challenging Yuriko Nishinotouin, she ends up partnered with Yumeko in the school's debt consolidation game and becomes something of an ally after their victory.
- Badass Normal: Being a Scholarship Student in a school where most students come from wealthy and influential families and are pretty much Born Winners, Mary's victories stand out because she has no advantage to play in gambles.
- Berserk Button: Other people trying to control her life, no matter how it might benefit her. For instance, when Kirari offers her a spot on the Student Council, despite it being something Mary's been considering going after, she walks out because she can tell Kirari sees her as more of a plaything than a person. And when Ririka uses Yumeko's poisoning by Miyo and Miri to force her to gamble for the presidential seat, Mary adds one stipulation to their deal: that she gets to punch Ririka afterwards.
- Breakout Character: Mary started off as the Starter Villain of the series, later getting upgraded to Aloof Ally to Yumeko before finally becoming the Deuteragonist of the series. Mary proved so popular that a prequel spinoff manga got greenlit and released, focusing on her backstory and her freshman year at the school. This came full circle when the Character Popularity Contest results were released in December 2017, with Mary voted by Japanese readers as #1.
- But Not Too Foreign: Between her first name and her hair color (which seems to be natural), it can be assumed that Mary has some level of Western ancestry. However, she is otherwise completely fluent in Japanese, has been living in Japan for apparently most or all of her life, and even the name "Mary" is spelled completely in Japanese Kanji (芽亜里) rather than the standard transliteration (katakana) used for the foreign version of it (メアリー). If spelled by syllable, the Romanized name should look more like "Meari."
- Cannot Spit It Out: While it has been downplayed so far, there's been scattered hints that Mary has a crush on Suzui. At the beginning of the series she got upset that Suzui was assigned to show Jabami around the school. Later on in the story when Jabami asks if Mary would be friends with her and Suzui, she first looks over to Suzui to read his expression before looking away blushing.
- Defeat Means Friendship: Her initial loss to Jabami sets off a chain of events that ends with the two more or less permanently allying in what the latter considers a friendship and Mary would rather call a grudging respect.
- Descent into Addiction: Futago details her transition from a relatively sane freshman into the psychotic gambler we meet at the beginning of the main series.
- Gambler's Fallacy: Saotome assumes that since she has around 21 of their thirty classmates voting to give her an advantage in her modified RockPaperScissors card game with Jabami, she's basically assured to win. It doesn't occur to her that still means there's a 12.4% chance on any given round Jabami will get a card Saotome's not expecting, which is what leads to her eventual loss.
- Girlish Pigtails: Her blonde twintails give her an innocent appearance, though it doesn't last long; when her true self is revealed, she's only a few grades short in terms of Zettai Ryouiki from being a classic Tsundere. In the live-action, whenever she's feeling particularly self-confident, she tends to fling her pigtails over her shoulder.
- Hero of Another Story: Mary has her own prequel series, Kakegurui: Futago ("Compulsive Gambler: Twin"), which details her experiences as a freshman that would shape her personality at the start of the main series one year later.
- He Who Fights Monsters: Futago reveals that, despite her stubbornness and temper, Mary used to be a fairly good person when she first entered Hyakkaou—after all, she got into gambling in the first place to free an old classmate (who she didn't even really like) from being a house pet. By the time Jabami shows up, however, she has since become just as cruel as the people unto whom her old classmate was at their mercy.
- Honor Before Reason:Futago showed this side of her. She once rejected the offer to join a group to dismantle Kirari because she witnesses the founder openly dismiss his (still-engaged) fiancée after she lost to Mary, and stood up against her opponent after the Score Comparing game despite her opponent conspire with the entire class to humiliate Mary
- It's All About Me: A rare relatively good version of this trope. Mary makes it her mission to dismantle the Student Council and House Pet system, not out of a moral desire but only after she was forced to suffer the abuse.
- Scholarship Student: Futago reveals that she belongs to a minority who came from families not as fabulously wealthy as those of the rest of the student body, and thus are frequently ostracized and challenged to matches for "intruding" into a heaven for Born Winners. Some students were interested in her & her skills instead, including 2 members of the Student Council who had already graduated by the time Yumeko transferred into the school
- Spanner in the Works: Ends up being the key for Jabami's victory against Yumemite when they have to guess her birth month (aside from her and Ryota, the audience was all members of Yumemite's fanclub and the members of the Student Council, whose birthdays she'd memorized). Amusingly, Jabami didn't even know it.
- Took a Level in Badass: Though she is already a good enough gambler to control 21 of her 30 classmates before Jabami shows up, she becomes a far more capable gambler after teaming up with Yumeko for the first time. She gains the attention of Ririka Momobami and effortlessly outsmarts Miyo and Miri (though admittedly they only had a basic understanding in terms of gambling) in the election.
- Trophy Wife: If her Life Schedule goes as planned, she would be forced into an Arranged Marriage with a politician known to be a Dirty Old Man. This indignity is one of the reasons she declines Kirari's offer to join the very Student Council that is making a fool out of her.
- Tsundere: After becoming friends with both Jabami and Suzui, she has problems dealing with their attempts to be friendly, trying to act aloof or verbally abuse them instead. The non-canon omake where she briefly works in a maid cafe to make a dent in her debts shows she has a problem taking compliments or almost any form of interest or affection from just about everyone. It later turns up in the manga proper. She acts aloof and annoyed when Yumeko gives her a ticket to Yumemite's concert and continues to do so during it. However, the stars in her eyes give off her true feelings and Itsuki's inner monologue has her noticing that Mary's actually extremely into the concert.
A boy relegated to house pet status by his inability to pay a sufficiently high "donation" to the Student Council, primarily kept under Mary's thumb after losing multiple poker games to her. He initially plans to drop out after Yumeko defeats her and is shocked when Yumeko splits her winnings with him, allowing him to buy himself out of debt - even though he'd been the linchpin of Mary's cheat during their match. Now, he's pretty much (given Yumeko's eccentricities) the closest thing she has to a best friend, and often tries (unsuccessfully, of course) to keep her from getting in over her head.
- Adaptational Personality Change: In the manga, Suzui is depicted as a rather plain guy, owning to his role as the Only Sane Man in the cast. In the live-action series, he is quite the Large Ham, reacting dramatically to pretty much every twist at every gamble he gets to see. He is also much more assertive in his attempts to get Yumeko to stop gambling against dangerous people (not that it helps; in fact, it almost makes her more eager to go for it).
- Born Lucky: Only in the yonkoma spinoff, where in one chapter he managed to get a huge serving of beef steak twice via getting 6 in a secret menu dice roll (compare Jabami & Mary who get fish head twice via getting 1 in a dice roll) and in another won a highly desired pudding in a 1 in 11 (consisting of The Student Council & Jabami's gang) lucky draw.
- Easily Distracted Referee: He is the dealer for Jabami's game against Ikishima, and all of them knew that he was going to help Jabami (in fact, Ikishima is counting on it).
- I Owe You My Life: After being saved from being a house pet by Jabami, he has always stood by her side and tries to help as much as he could: offering her some money when Jabami becomes a house pet in turn, being a dealer in her match against Ikishima, and later aiding her against Miyo and Miri.
- Morality Pet: Despite her obsession with gambling, Jabami legitimately cares for him and takes it uncharacteristically personal when Midari accuses her of using him as a pawn.
- Nice Guy: He is too good-hearted to be in such a cutthroat school as Hyakkaou, so much so he has little qualms admitting Mary, the same girl who defeated him into becoming a house pet, into his circle of friends with Jabami.
- The One Guy: Of the main Power Trio.
- Only Sane Man: He is one of the few student-gamblers who thinks the levels of gambling going on at the school is completely nuts, and even tries to drop out at the end of the first episode. It's only thanks to Jabami giving him the money to buy himself out of slavery as a mere tip that he even bothers to stick around.
- The Power of Trust: Probably his defining trait is that he has faith that somehow, against all odds, Jabami (and, to a lesser extent, Mary) can sway their games in their favor.
- Prevent the War: He often tries (unsuccessfully) to keep Jabami from gambling in ridiculously high stakes. He has since largely given up on it as the series goes on, instead speaking out at the potential unfairness that he could think of (like Erimi's Finger Guillotine).
- Ridiculously Average Guy: Save for his kindness and devotion to Jabami, nothing about him is particularly impressive, something he readily admits—he isn't as tough as most of the other male students, as cunning as the majority of the school's gamblers, or even that rich (his parents had to scrimp to get him into Hyakkaou to begin with).
- Spanner in the Works: Hopes to become this by aiding Jabami against Miyo & Miri in the 9 Nim game, which succeeds as it enables Jabami (and later Mary when Jabami is poisoned) to use his cards as an advantage against both of them.
- Toxic Friend Influence: A very subdued example, but over the course of the series, he has grown accustomed to Jabami's Wild Card tendencies, to the point that he admits he's starting to have feelings for her simply out of fascination with the chaos she gleefully throws herself (and all of Hyakkaou) into.
- The Watson: Due to his inexperience, he is regularly used as someone for Jabami to explain how she saw through the schemes of the various cheaters she gets into games with. That said, in the manga as a referee during Ikishima's game, he showed a good enough insight that enables him and Jabami to match all their cards in the second round.
The Student Council
Student Council President of Hyakkaou Private Academy and heiress to the leading clan of the Hundred Devouring Families conglomerate. After winning her position from the former president in a game of chance, she tightened the school's gambling and house pet systems, allowing Hyakkaou to essentially control the future of Japan.
- Animal Motifs: Sort of. She has a conversation with Jabami where she compares the environment she's created at Hyakkaou to an aquarium, with the students being fish she can kill or replace at ease (and later describes Jabami to the Council as an introduced predator wreaking havoc). The anime's opening credits heavily features fish—and to a lesser extent, characters turning into bubbles—as a result, and the anime itself upgrades the Council room to include a huge aquarium.
- Arc Villain: Downplayed example for the first arc. On one hand, everything weird and flat-out bad with Hyakkaou can be ultimately traced back to her—from the house pet system to the Life Schedules, her presence looms large over the school, especially given that her position can potentially make her a shadow dictator of Japan of sorts. On the other hand, she seems to be less interested in attaining power as she is driven by pure curiosity, going so far as to wager her presidency.
- Blue and Orange Morality: As mentioned below, she more or less shares Jabami's fascination with absurd risk-taking, though Kirari differs slightly in that she's also interested in utterly controlling peoples lives.
- The Dreaded: Her gambling skills are so outlandish great and her own personality is so imposing that nobody dares to go after her, specially head on. Even those who do find themselves regretting dearly. Everyone even treats Yumeko's idea of playing against her as complete madness.
- Face Framed in Shadow: In the live-action series, her face is never seen at all, always covered in either shadows or light, though her unique hairstyle is identifiable.
- Fiction 500: She's able to construct a massive, hi-tech tower that serves no use other than indulging her very specific gambling interests. She even points out that she hadn't been able to find a use for it until Jabami and Sayaka's match.
- Icy Blue Eyes: She's an icy beauty who treats other humans as her playthings, and has completely blue eyes.
- It Amused Me: Since she's brilliant, charismatic, and obscenely wealthy, this is basically her motivation for doing anything, such as offering Sayaka (who initially hated gambling) and Mary (who fought her way out of being a house pet despite amassing a really huge debt) spots on the Student Council. It's also why she forced Ikishima to gouge out her eye (she'd never seen the back of an eyeball before, comparing it to the dark side of the moon) and why she's been enforcing such draconian gambling policies at Hyakkaou (she read about how medieval rulers used gambling to manipulate the masses and decided on a whim to recreate their systems). And then she decides to gamble her very control of the school.
- Meaningful Name: Like Jabami, her surname contains the character for "devour" (as they seem to be related). Taken in conjunction with momo/peach, a fruit commonly portrayed as an Immortality Inducer in Japanese culture, it serves to underscore how absolute—godlike, even—her control over Hyakkaou is.
- Not So Different: Despite being on opposing factions, she and Jabami share a lot in common, in particular their penchant for irrational thinking.
- Opposites Attract: She admits that Sayaka's logical driven mind amazes her for being so different from how Kirari herself is and thinks, making her someone interesting and attractive to her.
- Pet the Dog: When Sayaka proves so devoted to her that she jumps from the Tower of Doors without hesitation, Kirari jumps after her and basically disregards the terms of their bet (that Sayaka forgets all about her), saying she likes her. Though this is somewhat muddied by her feelings of amusement that Sayaka jumped from the one door that wouldn't kill her without realizing it, as well as the fact that she did accept said bet in the first place on Sayaka's behalf (and despite her obvious distress).
- Schoolgirl Lesbian: It's apparent that she not only is aware of Sayaka's feelings for her but reciprocates them as well.
- Student Council President: She ascended into this position on her first year alone, and is now on her third straight year.
- Title Card: How she "speaks" in the live-action adaptation.
- Villainous Rescue: Cheated for Nishinotouin against Jabami in order to save her from losing around ¥2 billion, though her real purpose for doing so was to make the latter a housepet in order to learn about her.
- White Hair, Black Heart: Her silver hair and seemingly angelic appearance belies a devilish personality and penchant for insane gambles.
- Why Don't You Just Shoot Him?: Kirari points out that she could easily have Yumeko kicked out of the school, or at least make it a rule that no one can gamble with her... but she won't, because she and Yumeko share a Complexity Addiction, and she wants to see how far they can take it.
A masked individual who rarely speaks.
- Adorkable: Ririka is only able to maintain to her confident persona whenever she has her mask on. The second it gets removed, she turns into a Shrinking Violet. This tends to make her the butt of the joke during her interactions with Mary, who has little patience for both sides of her personality.
- Always Identical Twins: She's Kirari's twin, and looks similar enough to fake being her to family members.
- Character Development: She ends up being forced into it in a small way. She claims she wants to genuinely be Mary's friend, but Mary quickly gets sick of her lack of independence, resulting in Ririka challenging Rin of her own accord to prove herself to Mary. Midway through the match, however, Mary tells her she's successfully proven herself in an attempt to get her to stop due to the stakes rising sky-high, but Ririka decides to continue the match anyways against Mary's wishes out of her own desire to defeat Rin. Mary's impressed enough by that to not protest it.
- Co-Dragons: With Runa, for the president. While she oversees matters related to The Clan, even being implied to be a part of the reason why Kirari is so powerful, Runa oversees matters related to the school and the gambling system formed there.
- Cool Mask: She wears one all times, though her silver hair is a dead giveaway that she is Kirari's twin sister.
- Enigmatic Minion: Spends most of her time standing silently beside Kirari, and compared to the rest of the student council, she doesn't seem particularly interested in maintaining order in the school (like Sayaka and Nishinotouin), manipulating the students (like Kirari and Manyuuda), or even just watching the chaos unfold (like Ikishima, Yumemite and Yomozuki). Given her timidity, it's entirely possible that she could be the Token Good Teammate and is simply under her sister's thumb. She does force Mary to go after the presidential seat in the Election Arc, but it remains to be seen whether this is an actual attempt to overthrow Kirari or part of a larger scheme of hers... or both.
- The Man Behind the Man: If Terano Toutoubami, spokesperson of the Momobami clan, is to be believed, Ririka is the true force behind Kirari's ascent to power.
- Shrinking Violet: Both times her mask is knocked off, she's reduced to a stammering doormat. She can impersonate Kirari's ruthlessness very well, as seen when she attends the family meeting in the latter's stead, but that may just be because she considers acting as her sister to be another "mask".
- Theme Twin Naming: "Ririka" and "Kirari" are anagrams of each other.
- Twin Switch: Periodically, she takes the place of her older sister to help her implement her cunning plans.
- Walking Spoiler: It's all but impossible to discuss this character without bringing up the fact that she's Kirari's identical twin sister.
The secretary of the Student Council.
- Battle Butler: In the debt recollection game, she's shown to have some skill with a taser and self-defense skills when she subdues Jun Kiwatari after he tries to attack Mary.
- Beware the Quiet Ones: While she seems to be a reserved and calm girl, her subduing of Kiwatari and telling him what he now owes in the debt recollection game shows that she's every bit as terrifying as the rest of the Student Council, especially in the anime, where she◊ tops it off◊ with a Nightmare Face.
- Break the Cutie: She's technically an antagonist, but boy, is it hard watching the psychological trauma she endures when her faith in Kirari gets tested. It started when Kirari left without warning, forcing her to try to rein in the feuding Council members; then it turns out she was hiding beneath Ririka's mask the whole time. When Kirari seemed to be less intent on expelling Jabami before she throws Hyakkaou into anarchy than she is interested in watching exactly that unfold, she becomes paranoid that the latter may be a new rival for Kirari's attention. Then when her challenge against Jabami was refused because she wasn't wagering anything of immense value, Kirari puts their relationship as wager, the stipulation being that should she lose, not only will she be disowned but will have to leap to her death off the Tower of Doors. She puts her all into solving the problems and climbing up, but she still loses to Jabami. Realizing that not only did she fail to truly understand Kirari, but that the Student Council President she admires and the Wild Card she despises are Not So Different, she bottoms out and willingly leaps to her doom.
- Bungled Suicide: After losing to Jabami, she leaps off the Tower of Doors as per stipulation. However, not only does Kirari also leap off for her, but it turns out that they landed on an inflatable cushion underneath the flowerbed surrounding the Tower of Doors — the one spot that would not kill them. It turns out Sayaka's so logic-driven that she subconsciously solved a hidden puzzle and chose the correct door to jump out of.
- Devoted to You: Her devotion towards study has changed to one to Kirari.
- Disc-One Final Boss: Sayaka is the last member of the Student Council that Yumeko faces off against in the first part of the manga.
- Dying Declaration of Love: To Kirari. Fortunately, she ends up not dying.
- Morality Pet: Kirari does actually care for her to some extent.
- Only Sane Man: Has a deep distrust of gambling, especially after seeing what happened to all her fellow Council members who discovered the dangers of playing with Jabami. The stress of this role is essentially what drives her to start the Tower of Doors challenge.
- Opposites Attract: A key part of her relationship with Kirari. What dazes her the most about her is how different they are which makes Kirari fascinating to her.
- Rage Breaking Point: The accumulated stress of Jabami's antics threatening the school's social order, Kirari being cold towards her before leaving, seeing the Student Council in shambles, and learning that Kirari was actually present for Yumemi and Manyuda's games, causes her to lash out against Jabami.
- Schoolgirl Lesbians: Very much for Kirari. The Tower of Doors game even has her carrying the lily in her mouth with what can only be described as bedroom eyes. It seems Kirari reciprocates as well.
- Sixth Ranger: A villainous version for the Student Council. She isn't exactly a member of the Council and isn't in charge of any part of it, aside from being Kirari's personal secretary and sometimes working as a spokesperson for her in some matters. She holds no power in the Council and is much more interested in the president than it.
- The Smart Girl: The brains of the Council, she has spent most of her middle-school years studying instead of gambling, to the point where she was rumored to be a genius by her peers. It's her intense devotion to logic that piqued Kirari's curiosity enough to recruit her when she was still in middle school.
- Villain Protagonist: In many ways, she's this during her match against Yumeko. The match is almost entirely from Sayaka's point of view where only her thoughts are shown, going into her mostly sympathetic background and goal of winning the president's love against an insane opponent that's destroying everything her cherished president created. Besides a brief period at the start that exclusively shows Yumeko instead of her, the focus is on Sayaka and her struggles for the rest of the match. She isn't a Smug Snake unlike other villains, doesn't cheat, and is portrayed as the underdog due to a mistake she made at the start. She also gets a twist heartwarming happy ending where Yumeko points out that even though Sayaka lost the match, she won what she wanted.
A rather youthful-looking member of the student council. She's the head of the Election Committee and personally serves as a referee during an election gambling match she felt to be important.
- Animal-Eared Headband: The hoodie variant. She wears a hoodie with rabbit ears over her uniform. They seem to be the uniforms of her referee squad, since the dealers who work under her all wear animal-eared hoodies.
- Berserk Button: Being accused of not being neutral is one.
- Bitch in Sheep's Clothing: Looks cute, but gleefully taunts Mary over being assigned a Life Schedule that involves marrying a politician apparently known to be a pedophile, even telling the latter that she should start brushing up on her skills in bed.
- Blue and Orange Morality: To her, the essence of absolute neutrality is that even the dead should have a chance to win. By proclaiming that statement, she implied she purposefully arranged the match against Miyo and Miri because she wasn't keen on them poisoning their way to victory. Given her sadistic personality, it's also a case of Even Evil Has Standards.
- Co-Dragons: Together with the Vice President, she seems to be directly under orders of the president alone. While she manages most of the school related stuff, the Vice President appears to oversee things related to The Clan for Kirari.
- Contralto of Danger: In the anime she usually speaks in a cute high-pitched voice, but when she's being serious or threatening someone her voice becomes significantly lower.
- Gamer Chick: She's often seen playing a handheld game console. In the live action series, it's explicitly a Nintendo Switch.
- Non-Action Guy: Aside from Kirari and Ririka, she is the only member of the Student Council who Jabami hasn't gambled with thus far, though it seems that it's because Runa is a dealer rather than a gambler, so she wouldn't play either way.
- Older Than They Look: She's obviously old enough to be on the student council, but she looks no older than ten.
- Sweet Tooth: Often seen with a lollipop, and her first major appearance shows her sitting at a table with candy scattered all over it.
- Token Mini-Moe: She's the youngest-looking of the student council members.
The treasurer of the student council, and the only male member.
- Aww, Look! They Really Do Love Each Other: One possible implied reason he was such a jerk to Itsuki and allowed her to be kicked out of the Student Council is because he didn't want her to suffer like he did, especially considering that he initially tried to persuade Itsuki to stay out by basically telling her the responsibilities of the Student Council were serious and not fun at all. It later becomes clear that he cares for Itsuki to some extent at the end of the Greater Good game, when he frantically tries to stop Miroslava from punching Itsuki in the face. Fortunately, Miroslava stops of her own accord, but even after that, Ibara still needs to calm Kaede down.
- Big Bad Wannabe: Despite his mental skills and egregious access to money, he is still very much inferior to Jabami and Kirari in the sense that he can't even compare to their insanity and love for gambling. When they're in equal ground on a match, he honestly can't keep up with the way they make everything riskier, not to mention that he is unable to factor in just how crazy Jabami is and the fact that there are some moments that all they'll rely is on luck alone.
- The Chessmaster: He is very analytical and is quick to factor in even a Wild Card like Jabami into his schemes.
- Cruel to Be Kind: It is implied that his dismissive attitude towards Itsuki, down to letting her be fired from the Student Council after losing to Yumeko in the latter's second match in the school alone, is borne from his desire to protect her from the same kinds of pressure he has been facing as a member of the Council.
- He's Back: Goaded by Yumeko during the Greater Good Game to start living again, he successfully analyzed who the traitors are just before the final match.
- I Just Want to Be Normal: Flashbacks during his gamble against Yumeko show that all he wanted to be as a kid was an air traffic controller, but his father wouldn't let him, and even threatened to disown him unless he succeeds at Hyakkaou. When he tried to dissuade Itsuki from joining the Student Council because it came with all sorts of burdensome responsibilities, he was probably being genuine about it. Even after he offered to let Itsuki back on the Council in the middle of his match against Yumeko, he was being so mean about it that he may have wanted her to reject the offer because he didn't want her to suffer the same fate he did.
- The One Guy: The only male in the student council.
- Out-Gambitted: Confident in his ability to predict and manipulate the actions of others, he nonetheless gets hit by this twofold. Not only do Jabami and Sumeragi play him like a fiddle for the entire climax of their poker game, but it also turns out that Kirari more or less knew what he was up to from the start.
- Prematurely Grey-Haired: Losing to Jabami and Itsuski, becoming a housepet, and being kicked off the council by Kirari turns his hair white from shock.
- The Starscream: He is openly jockeying for the presidency, and he sees no problem backstabbing his fellow members along the way. After Yumemite outs him in front of her fanbase for letting her lose to Jabami, he claims he regrets nothing with how the situation turned out, knowing that he'll benefit regardless of who won (had Yumemite lost which she did, that's one less competition; conversely, had Jabami lost, that's one more credential to his name).
- Self-Deprecation: Losing to Jabami & Sumeragi utterly destroyed his self-confidence to the point that he lost his sense of self. Even Itsuki trying to enrage him with words got no reaction from him. It took him participating in the Greater Good Game and a goading by Jabami to return to his old self.
- Villainous BSoD: After losing to Jabami and Sumeragi and being fired from the Council, he falls into a coma that lasted several weeks, awakening only at the end of the first week of the Presidential Elections.
- "Well Done, Son!" Guy: Like Sumeragi, his father has threatened to disown him should he not utterly dominate at Hyakkaou.
An up-and-coming Idol Singer who used the votes from her fans to get onto the student council, where she serves as head of public relations. Though she acts like a typical cheerful and perky idol to the public, she greatly dislikes her fans and secretly aims to become an Academy Award-winning actress in Hollywood.
- Alliterative Name: Yumemi Yumemite
- Berserk Button: Endangering her career, despite how much she also despises it. She is totally livid towards Jabami for planting a listening device to increase her wager, and then Manyuda for giving Jabami the ammo (a fan letter that she'd torn up and the very listening device that Jabami would later use). She also hates being upstaged, seeing her fan club's coordinated dances as an insult since it means they aren't totally devoted to her performances.
- Bitch in Sheep's Clothing: Beneath her cute demeanor, she hides a lot of anger towards her fans, but needs to be friendly in order for them to keep supporting her. After Jabami plants a recording device of her rant, she vows to severely tarnish Jabami's reputation (by making her star in porn and sleep with producers) as her costar, so that she'll look more innocent by comparison.
- Break the Haughty: Her game against Warakubami hits her very hard, realizing that in terms of skills, strategy and even resolve, she couldn't win against her. This leads to her trying to lose in order to make herself feel better, before resolving to win anyways so she can continue finding her purpose in life. By the end of the game she just breaks down crying from the sheer pressure.
- Crocodile Tears: Saotome believes she did this when Yumemi's fans told her that they love her despite knowing how she truly feels about them.
- Defeat Means Friendship: After losing to Yumeko and finding out that her fans still love her despite knowing her true colors, she gains a much higher opinion about Yumeko and invites her to perform alongside her after the match.
- Evil Virtues: For all her less-than-stellar personality, her work ethic, dedication, and determination to succeed and thus reach her dream of becoming an actress worthy of Hollywood is pretty laudable.
- Exotic Eye Designs: She has star-shaped pupils. They disappear when she's not putting up her cutesy idol persona, though.
- Freudian Excuse: Her determination to succeed and adaptation to Hyakkaou's brand of Social Darwinism is rooted from a childhood experience of her mother telling her bluntly that a Japanese girl would probably never become an actress worthy of Hollywood.
- Girlish Pigtails: Of the "two side up" variety, adding to her image as a girlish and cutesy Idol Singer.
- Hard Work Fallacy: Takes her path towards stardom very seriously. From childhood, she essentially gave up any chance at a normal, free life to undergo the harsh training required of an idol, and attends Hyakkaou in order to build up the success she'll need to become an international star. It is precisely that reason why in the prequel, Kirari ended up being interested enough to invite her to the Student Council because of her determination.
- Hates the Job, Loves the Limelight: She doesn't actually like being an idol, especially since she has to put up with obsessive fanboys, but she's still dedicated to her career because she needs the support and connections she's making at Hyakkaou in order to realize her true goal of becoming an actress worthy of Hollywood.
- Hero-Worshipper: For the red carpet stars of Hollywood.
- I Gave My Word: After losing to Yumeko, her secretary Saori desperately tries to bribe Yumeko into not playing taped audio evidence of Yumemi's misgivings towards her fanbase. Yumemi herself relents, however, and chooses to abide by the stipulations of their game. Either way, her fans didn't care much, and expressed that they still love her anyways.
- Idol Singer: A member of the Student Council who is also a famous idol. However, she's mainly using her idol career as a stepping stone to becoming a Hollywood actress.
- Loophole Abuse: After a week the Presidential Election started, she got around 100 votes by using her fanbase. The votes must be earned through gambling in official matches, but there's no rule against cheating that goes undiscovered or that neither player minds, so they can just give her the votes through a set up match.
- Meaningful Name: Yume means dream, as in her dream of being a Hollywood actress. She wants Yumeko as her costar since she also has the character for "dream" in her name.
- Miss Fanservice: Of all the characters, she is the first one to show Ecchi-levels of fanservice as a metaphor during her battle against Warakubami.
- Nice Character, Mean Actor: She puts on a show of being your typical cheerful and cutesy Idol Singer, but in reality she has a very low opinion of her fans, viewing them as disgusting and perverted (though this isn't entirely unfounded, given how obsessive the president of her fan club is shown to be).
- Now What?: During the game against Warakubami, she realized she didn't think about what happens next after winning. Eventually, she chose to keep winning anyway to figure it out.
- Pyrrhic Victory: How she feels about winning against Warakubami in the Soxiante-Trois game, as she won because she just knows how to game the system and not because of her preferred skills (acting).
- Repetitive Name: Yumemi Yumemite.
- Rule of Drama: Her preferred method of gambling is to raise up the confidence of her opponent and then crush them so that it comes off as a plucky underdog's victory. In her gamble against Jabami, she intentionally throws games that she could have won, planning to sweep the remaining games when Jabami has almost won.
- Signature Song: In the main series, "Russian Roulette of Love", according to the yonkoma, she is the song writer and her inspiration comes from Ikishima of all people in a cafe.
- Warts and All: Despite being forced to confess to hating her own fans as part of her agreement should she lose her gamble against Yumeko, her fans express that they still love her regardless, encouraging her to keep performing for them.
Head of the Beautification Club. She intervenes when Yumeko, reduced to house pet status, is menaced by a group of male students, pulling a gun on them and reacting with disappointment when they walk away rather than indulge her. When she hears the rumors about Yumeko's gambling addiction, Midari realizes she might be the opponent she's been looking for and kidnaps Yumeko (alongside Suzui) to force her into a game before she can challenge Kirari, who Midari believes would 'decimate' her.
- Abhorrent Admirer: She's become this to Yumeko, not so much because of her violent stalker-ish tendencies, but because her need to feel pain usually conflicts with Yumeko's desire for a thrilling, unpredictable game. She had the chance to bond with Yumeko in the Finger Guillotine game, but squanders it by cutting both of the last 2 strings, making Yumeko hate her even more.
- A Date with Rosie Palms: Multiple times, after discussing or fantasizing about Yumeko, she abruptly leaves council meetings for the bathroom, and no, there's no question about why, especially in the anime. The live-action seriously toes the line with portraying this; while the game against Yumeko is being set up, during her narration, she's moaning very loudly, and though it's not shown moving at all, one of her hands is on top of her skirt.
- Ax-Crazy: Stands out as this even in Hyakkaou, as she revels in violence and has the overwhelming desire to play games that have a high chance of ending in her own death.
- Axes at School: Carries a gun around in her purse, though it seems that the majority of the students think it's a very realistic-looking airgun or just a model. It isn't.
- Blue and Orange Morality: The only thing that makes her happy in life is insanity. Even her current obsession with bringing pain and potential death on herself is fed by this, and it's why she falls completely in love with Yumeko after realizing that even by her own standards Yumeko's crazier than her.Midari: She's fucking nuts! Way more than I ever imagined! A person that goes above and beyond even my wildest dreams...
- Cardboard Prison: In the live-action, her place inside the student council chambers is in a cage off to the side. It serves no real purpose other than to highlight her derangement and her peculiar position within the student council.
- Combat Sadomasochist: She felt real excitement for the first time when she gouged out her left eye, and decided that her ultimate thrill could only come from death by gambling. And is absolutely ecstatic about the Finger Guillotine game.
- In her spin-off, her first game as a member of the Student Council is being a dealer for game akin to Five Finger Fillet (though instead of a knife the tool is the sharp tip of a compass). The hand in place? It's Midari herself, and even when the second participant decided to stab her hand just to become quicker, Midari felt pleasure from the pain, and offered that participant (who won and got her debt cleared) a role as a member of the Beautification Club.
- Convenient Weakness Placement: The room where Jabami and Mushibami set up the Finger Guillotine happens to be a place where the members of the Beautification Club hang out. Given all the other tropes listed here, Mushibami's luck was really bad that day.
- Death Seeker: The reason she joined the council? Kirari promised to kill her someday if she did. Though waiting so long has driven Midari mad with masochistic yearning, which is why she tries losing to Yumeko on purpose.
- Depraved Bisexual: It's strongly implied that the sex of her partner is not important for her, if they can bring her enough pain to excite her.
- Eye Scream: Sometime ago Ikishima accumulated a debt of ¥300 million to Kirari, and she paid it by tearing out her left eye with her own hands.
- Fridge Logic: In-universe. In chapter 50, she questions why is Yumemi playing idol if she wants an Academy Award, since even without a career of an idol as stepping stone, Japanese actress still managed to go to Hollywood before. She comes to the conclusion that Yumemi is trying to hide her lack of legitimate acting talent through her popularity.
- Happiness in Slavery: What she wants, although Yumeko is too disgusted by her to pursue it. Immediately after accusing Yumeko of treating Suzui more like a slave than a friend, she states she'd find nothing but bliss in Yumeko controlling everything about her life.
- Hero of Another Story: Has her own spinoff called "Kakegurui Midari", starting when she begins her role in the Student Council.
- Love Confession: Makes one to Yumeko in episode 7, when she realizes Yumeko's devotion to complete chance no matter the situation is even crazier and thus more wonderful than her devotion to assured suffering.Midari: Yumeko! You're... my Goddess! Yumeko! P-Please wait! Y-Yume... I-It can't be anyone else! Just one bullet's fine! I'm begging you, please make me suffer!
- Meaningful Name: Her given name, "Midari" can be read as "reckless", fitting well with her desire to gamble in order to lose as badly and as often as possible.
- Nice Job Fixing It, Villain!: More "psycho" than "villain", but just when she began getting into Yumeko's good graces during the Finger Guillotine game, she lets her masochism run loose yet again and cuts the last two strings simultaneously, not only disqualifying her and leaving Yumeko the sole winner (Erimi having withdrawn her finger at the last second), but also earning her the latter's eternal scorn for turning a "perfect" 50-50 gamble into a 100% certainty.
- Nightmare Fetishist: Like Yumeko, she doesn't mind if she loses badly and is taken advantage of. In her initial appearance, she even tells the bullies demanding that Yumeko strip that, should she lose their game of Russian roulette, a gunshot wound would prevent her from resisting whatever they wanted to do to her.
- Russian Roulette: Her trademark game. She even plays it by herself if no one else will indulge her, which is often. Her obsession with it, which clearly holds her back in terms of creativity, is likely another reason that Yumeko finds her irritating.
- Villainous Crush: Falls madly in love with Yumeko, after Yumeko engineers a draw between them because she doesn't appreciate Midari rigging the game to remove any actual risk to Yumeko, even if the stakes were getting shot.
Head of the Culture Club. Mary uses her one right to a public match as a house pet against her, but is defeated and saddled with an even larger debt. As planned, this attracts the attention of Yumeko, though Yuriko soon discovers she may be in over her head.
- Badass Decay: Arguably gets hit the hardest of this out of any of the Student Council members. After her defeat at Yumeko's hands, Yuriko frequently get portrayed as being a nervous wreck and she's the most out of her depth during the Hundred Devouring Families arc. Could also be a case of Reality Ensues, as Yuriko, unlike majority of the other characters in the show has never been shown as being a particularly skilled gambler. There was only one specific game she favored that she specifically rigged in her favor.
- The Cassandra: After nearly losing to Yumeko (and having to be bailed out by Kirari), she becomes much more of a contrarian, especially whenever a fellow Council member sets his/her sights on Yumeko, often to little avail.
- Eyes Always Shut: Except briefly, when Yumeko makes her very mad. In the live-action version, they're wide open when Jabami bets every last chip on 24.
- Flat Character: She doesn't have a lot of additional characterization compared to the other Student Council members, and her role is diminished after losing to Miyo & Miri during the Presidential Election (which is very early in the storyline). And unlike Ikishima, she does not have her own spin-off to compensate for this.
- Pet the Dog: While Yumeko is right when pointing out that she's little better than a cowardly loan shark at heart, her internal monologue after she realizes she might end up losing ¥217 million reveals that her primary motivation for joining the student council was to keep her club members from becoming house pets, and she's clearly horrified by the prospect of that fate befalling them if she has to use their donation money as collateral.
- Punny Name: During their Life and Death match, Jabami points out how Nishinotoin's name translates to 2-4-10-in while skipping 6 and 8.
- Raven Hair, Ivory Skin: Which is to be expected from the character with a stereotypical Yamato Nadeshiko design.
- Screw the Rules, I Have Money!: The trick she and her club members have set up isn't guaranteed to let her win all the time, but she has such large coffers that her losses have never affected her. Yumeko criticizes her for relying on her fortune instead of chance or wit.
- The Worf Effect: While she is definitely not the strongest gambler, her losing to Miyo and Miri (due to being unknowingly poisoned by them) showed that the Hundred Devouring Families can be as nasty as the Student Council.
- Yamato Nadeshiko: Basically comes with the job. She plays the trope even straighter than Yumeko, not only having the looks and the inner steel but also with how she only ever wears traditional Japanese clothing.
The second student defeated by Yumeko. Daughter of a highly-successful toy company owner, she paid an exorbitant amount for a spot on the student council. She challenges Yumeko to a rigged game of Memory Flip with the intention of adding one of Yumeko's fingernails to her collection, but after her trick is exposed, she breaks down in the face of Yumeko's bloodlust and loses her position. Later, having heard that Yumeko intends on gambling with Kirari, she assumes that Yumeko intends to become the new president and throws her lot in with the main trio in hopes of getting back on top.
- Ambiguously Bi: Noticeably blushes and grins ecstatically when she sees Yumeko's idol outfit, proclaiming that she likes the view. However, by chapter 48, her crush on Manyuda has reached Everyone Can See It status, In-Universe and out.
- Collector of the Strange: Has a collection of fingernails from girls who lost to her.
- A Day in the Limelight: More than her introductory arc, the Jabami-Manyuda match has become this for her.
- Didn't Think This Through: During the Idol Arc, Sumeragi decides to back Yumeko because she believes that Yumeko's drive will be her quickest path to getting back to the top of the hierarchy at the school. She's quick to realize during Yumeko's duel with Manyuda, that Yumeko has no real ambitions outside of gambling for the sake of gambling and an alliance with Yumeko will just as likely result in Yumeko dragging her down with her should she lose. While Sumeragi still allies with and remains friendly with Yumeko, the duel is also a quick reminder that she can't simply use Yumeko to get her way back to the top.
- "Do It Yourself" Theme Tune: Yuki Wakai, her voice actress, is part of the five-man J-Pop group D.Selections, which performed the ending theme, "LAYon-theLINE".
- The Dog Bites Back: After having been used by Manyuda as a pawn en route to his own ascent to the Student Council presidency (and still having the gall to invite her back to the Council), she decides she's had enough and sides with Jabami, culminating in them double-teaming him near-effortlessly.
- Fingore: Her preferred prize for winning a high-stakes game is to rip off the fingernails or even toenails of girls she defeated. Later, when committing to Yumeko's plan to bet her inheritance against Manyuda, she shows her determination by tearing her own fingernails off with her teeth.
- HeelFace Turn: Though she's offered the chance to back down, she ends up publicly defying the student council by helping Yumeko gamble against Manyuda with her inheritance.
- Inelegant Blubbering: After losing to Jabami in their second match, she is reduced to crying uncontrollably after the latter scares her out of her wits with demands of a third match with the wager being all of the loser's nails.
- It Only Works Once: The reason why she loses her Memory Flip match to Yumeko. She uses a trick deck with a thermal pattern on its back (there are heaters in her bag) that fades away after three minutes, allowing her to know the placement of various cards. She's able to beat Yumeko the first time due to this, and when the latter demands a rematch, she tries to win again using an identical deck. Unfortunately for her, Yumeko has already picked up on the trick and was able to win the rematch in a single turn now that she knew what to look for. Yumeko even points out that she probably would've lost had Itsuki prepared a deck with a different pattern.
- Mistreatment-Induced Betrayal: Her defiance against the Student Council is largely motivated by Manyuda taunting her as "talentless" when she'd previously thought they were in the same boat.
- Obfuscating Stupidity: Though Yumeko defeated her quite soundly, Manyuda writing her off as someone with no gambling skills causes him to fall for their trap, something that they soundly taunt him for while springing it. The Student Council President actually has to ask how much of Sumeragi's prior uncertainty was an act. Even more hilarious, during the Presidential Election arc she is able to accumulate 50 votes in her first week, making her the only first year to reach the top 10 of that period.
- Oh, Crap!: When she realizes Yumeko has cottoned on to her trick, as it would obviously be bad for PR if people learned that her father's company was manufacturing marked cards.
- Professional Butt-Kisser: She uses her gambling matches to advertise the cards and other gaming supplies made by her parents company. The anime even has her stream her match with Yumeko. After she gets kicked from the student council due to losing to Jabami and her lack of ability, she tries to cozy up to Jabami in order to get a spot back.
- Screw the Rules, I Have Money!: She uses her massive funds to pay for a seat in the Student Council (for a while), purchased 3 really expensive Yumemite tickets for Jabami's group, and during the Presidential Election it's revealed that she bribed some students to fix matches for her. Ironically, her first match against Jabami doesn't use this.
- Shipper on Deck: Seems to be one for Ryota/Yumeko, given how ecstatic she gets over what was essentially a love confession from the former to the latter in episode 12.
- Unreliable Narrator: During the Greater Good Game, she keeps making monologues about how the traitor will screw up everyone, misleading the reader to the fact that the mastermind behind the cheating is herself.
- Unwitting Pawn: She genuinely thought Manyuda was her friend because they both shared the same parental pressure for greatness and their aspirations for climbing up the Student Council hierarchy. She never realized that she was but his stepping-stone in his ambitions for Kirari's seat until she was booted off the Council after losing to Jabami.
- "Well Done, Son!" Guy: Her father is willing to disown her if she doesn't provide good results in Hyakkao via good connections with the Student Council, which is why she goes crawling to Yumeko upon being kicked off the council.
- Xanatos Gambit: She made an outside bet with Terano over whether or not Kaede would be able to make it to the end of the Greater Good Game. She sees this as it: if Kaede didn't as she had bet on, she'd win an extra of 300 votes, if Kaede pushed himself back together, Kaede would be back on his feet and she could stake her faith on him. Jabami states that a inversion of this trope is also true, if Kaede won, then she'd lose 300 votes and if he lost, it'd probably mean that the man she loves is lost forever.
- Zettai Ryouiki: She wears over the knee length socks with star patterns.
The Hundred Devouring Families
The various representatives of the clans that are a part of Kirari and Yumeko's extended family. They were selected by their respective clans to transfer to Hyakkaou Private Academy for the sake of removing Kirari from her seat of power in the upcoming elections. They each come from different competing branches of the family and are thus are all rivals to each other and technically rivals to Yumeko as well, but the common goal of usurping Kirari has united them all. Barely. Although they are attempting to defeat Kirari, they end up becoming antagonists to Yumeko instead due to various circumstances.
- Enemy Mine: Downplayed. All of them want to be the heads of The Clan, however, they prioritize taking Kirari down over who exactly gets to be the head, and it's lightly implied they know they have a better chance by supporting Terano than fighting each other.
- Family Theme Naming: All their surnames share the -"bami" suffix, which can be translated as "devouring".
- Strong, but Unskilled: Turns out most of the members have a basic understanding of the games used in gambling, but they have honed specialties & killer instinct that enables them to end up as the front-runners of the Presidential Election.
- Villain of Another Story: Played with. They definitely share the story with Yumeko and the other mains and get involved with her quite easily, however, the families have no actual interest in facing against Yumeko or Saotome if not for their votes. They're actually working as antagonists for Kirari, rather than any of the manga's actual leads.
The ringleader of the Hundred Devouring Families' alliance against Kirari. She brought all the representatives together for the sake of finally beating her.
- Alliterative Name: Terano Totobami
- Arc Villain: A downplayed version for the Student Election Arc, being the ringleader of an alliance of Kirari's (and possibly Yumeko's) extended family members with the intention of unseating her from the presidency; Yumeko just happens to keep getting in their way.
- Arch-Enemy: To Kirari, although the latter thinks of her as more of a nuisance due to their sheer ability gap (and that the only reason she even has an opportunity to challenge Kirari was because the latter arranged for the election in the first place). In fact, she hates Kirari with such a passion that she forged a tenuous alliance with fellow Momobami clan members with the intent of finally unseating her.
- Friendly Enemy: Despite her plans going awry because Yumeko keeps defeating the other clan representatives, she's still willing to have tea with Yumeko and hear out her ideas. This is in part because she's aware that Yumeko is the one being dragged into those matches instead of the other way around.
- Genius Cripple: Though wheelchair-bound, she is more or less the brains and the glue that keeps her alliance together.
- Handicapped Badass: She is in a wheelchair, having an assistant that pushes it around. However, she is the ringleader and mastermind behind the the families' attempt to take power from Kirari. She is also in second place in the first election round, meaning she is the biggest threat to Kirari (though yet not enough for Kirari to consider her at all).
- Villain Respect: To Yumeko (but not to her arch enemy Kirari, whom she despises with a passion and refers to with extremely derogatory terms). While explaining to Ibara that Yumeko wasn't joining their alliance, she states that if Yumeko really wanted to defeat Kirari, she would have done so already, showing that Terano views Yumeko as even more capable than her arch foe.
- We Win... Because You Didn't: While she expresses that she'd prefer it if she wins the elections, she also expressed that she wouldn't mind anyone else (including her alliance) beating her, so long as it isn't Kirari (or at least members of her cabinet).
A member of the Totobami family who accompanies Terano in her quest to bring down Kirari.
- The Caretaker: She mainly serves as the one pushing Terano's wheelchair.
- Cute Little Fangs: To go with her vivacious personality.
- Dark-Skinned Blonde: She has slightly tanned skin and blonde hair.
- Genki Girl: So far she has been this in contrast with the Bitch in Sheep's Clothing most characters are.
- Gyaru Girl: Which serves as contrast with the more proper-looking Terano.
A young girl in Gothic clothing whose family is in the business of torture, and the first member of the Hundred Devouring Families who Yumeko gambles against during the Election Arc.
- Bratty Half-Pint: As small as a child and rude to almost everybody she meets.
- Elegant Gothic Lolita: Instead of Hyakkaou's uniform, she wears gothic lolita clothing.
- Game of Chicken: She has a game called the "Finger Cutting Guillotine". In the game, up to three people put their fingers in holes bellow a guillotine that is held by a single string among twenty. The players don't know which string will set the guillotine down and in each of their turn, must cut one string. The person who kept their finger under the guillotine for the longest time wins.
- Hoist by His Own Petard: The Finger Guillotine secretly has an iron bar installed that prevents the blade from cutting anyone's fingers off, so her opponents usually tremble while she cuts the strings without any risk. The tables are turned when she begins to suspect Yumeko has discovered this and had said bar removed (but can't speak up about it), so she's the one slowly sinking into panic during her game with Yumeko and Midari, who are head-over-heels loving the danger. To her credit (as noted by Yumeko), she had the conviction to stay in the game anyways until the very last moment even after believing her finger was now at risk.
- Mismatched Eyes: Her anime design reveals her left eye is blue while her right one is red.
- Mugging the Monster: Her internal monologue during the Finger Guillotine game is gloating about how no one can endure the unpredictable risk of losing a finger for long and will naturally crack under the pressure. She ends up gambling with probably the two biggest sadomasochists in the cast.
- Stress Vomit: The pressure and the insanity of Yumeko and Midari make her vomit in her mouth.
- Suicidal Overconfidence: She goes after Yumeko because of the rumors surrounding her, believing she'll easily take down the one who's caused so much trouble for Kirari. The rest of the family representatives warn her not to go after Yumeko (at least, not that early). Yumeko, of course, pretty much wipes the floor with her.
- Tears of Fear: Midway through the match, she begins crying in absolute terror over the sheer insanity of Yumeko and Midari, as well as the risk of actually losing a finger when she begins thinking that the former may have known of the iron bar placed above the Finger Guilloting and secretly had it removed.
- Villain Ball: She decides to challenge Yumeko, even though Yumeko is an enemy feared by her peers and she is warned against it, but she decides not only she can definitely take Yumeko down, but will do so as soon as possible, when her loss will kick her out of the competition and her victory will only earn her one vote.
- Warm-Up Boss: She is the first member of the Devouring Families faced by the protagonists. She is actually quite smart and if her opponent wasn't Yumeko, she'd probably win.
- Worthy Opponent: Despite losing to Yumeko (in her own game, no less), the latter praises her conviction. Erimi might have lost, but she nevertheless managed to stay in the game despite breaking down in fear midway through the match, only withdrawing her finger at the last second after Midari changed the game from "possible finger suicide" to "guaranteed finger suicide" by cutting the last two strings at once (though the secret iron bar ultimately protected their index fingers). Because of that, Erimi earned Yumeko's respect while Midari got her eternal scorn.
A specialist in poison. She and Miri Youbami are childhood friends who were like sisters to each other before the nature of their clans' competition forced them apart. They secretly kept their bond with each other in spite of that and work together during the election arc. Their poisoning of Yuriko to sabotage their match with her catches Runa's attention, and in retribution, Runa arranges for Yumeko to gamble against them.
- Didn't Think This Through: Mary points out in their match together that most high-level Hyakkaou students have already been in gambling matches where death or even a Fate Worse than Death was on the line, to the point they're Conditioned to Accept Horror, so trying to threaten her or Suzui with lethal poisoning to change how they play is more or less pointless.
- Failed a Spot Check: The reason she and Miri lost their game to Suzui & Saotome. She was too focused on her poison that she ignored her surroundings, especially in round 3 when Runa did a Gilbreath shuffle that benefited Suzui & Saotome
- Honor Before Reason: Suzui and Saotome are surprised to find she's actually willing to honor their bet and inject her passed out sister with another dose of lethal poison, despite looking down on gambling earlier.
- Kick the Morality Pet: While she loves her sister, her love seems to reach a limit when she threatens her sister into taking the fall despite how Miri would have done so anyways. She's also still willing to inject Miri with more poison after they've lost their game against Saotome and Suzui, just to honor their bet. She does quickly put Miri on her back and run to get another batch of antidote to cure her afterwards, though.
- Might Makes Right: She and Miri believe that gambling is a waste of time, and their preferred method of "gambling" consists of poisoning "stronger" opponents (like Nishitounin and Jabami) before the game officially starts, and coercing "weaker" players (like Suzui and Saotome) with the antidotes for their friends if they just give up, and similar poisoning if they don't.
- Mindlink Mates: She and Miri are so good at reading each other that they can communicate through simple body movements.
- Rapunzel Hair: Her hair reaches past her waist.
- Wake-Up Call Boss: The battle against Miyo starts with her poisoning Yumeko, forcing Suzui and Mary to fight by themselves for her life. She is the first one to show that the Devouring Families mean business and that they are to be feared in a game.
Miyo's childhood friend. She is a quiet girl who is submissive to all her friend's wishes.
- Mindlink Mates: She and Miyo are so good at reading each other that they can communicate through simple body movements.
- Not So Stoic: She usually shows an impassive face with little expression, but nearing the end of their game against Yumeko, she starts to show fear and sadness as Miyo betrays her and she has to poison herself to save her.
- Odango Hair: Her hair has two buns atop of it.
- The Quiet One: She prefers to let Miyo do the talking, staying quiet by her side.
- Token Mini-Moe: She's considerably smaller than her sister and most of the other characters, for that matter, and is considerably cuter.
- Undying Loyalty: She is willing to put her own life at risk for Miyo's objectives, which is proven when she purposefully loses a second game so that Miyo won't get poisoned or lose the election.
Member of the Honebami clan, she comes from a family specialized in "Cleaning". She is scary, quiet and has an icy demeanor.
- Action Girl: Her family specializes in "clean-up", where they get rid of the impurities in the family. Judging how quick & efficient she was in capturing Itsuki...
- Buxom Is Better: Probably the biggest bust in the entire series.
- Cold-Blooded Torture: Mira proposes this as a way to get the traitor in their match to confess. She comments that even though torture was more Erimi's specialty, she's more than good enough at it.
- Contralto of Danger: The woman has a pretty deep voice, and she's not someone to mess with.
- Defeat Means Friendship: Being fooled by Itsuki, she grows to respect her, and not only gracefully accepts defeat, but also promises to keep her secret about Kaede safe.
- Defrosting Ice Queen: She's completely serious and stoic at first, but by the end realizes she enjoyed the gamble and is nice enough to keep Itsuki's feelings for Kaede a secret.
- Foil: To Ibara, who's extremely passionate and rude while Mira is The Stoic. Lampshaded when the two realize that their match is a chance to take Yumeko's votes. Despite the inner narrative showing they both feel that Yumeko and Itsuki's votes are "ripe for the picking", Ibara has an Ax-Crazy Slasher Smile while Mira has her same apathetic expression except the lighting and the angle makes it look more ferocious.
- Graceful Loser: Despite going berserk on Itsuki at the start after Manyunda exposed their plans, she quickly calms herself afterward and praises her gambling skills, admiting that strategy has never been her forte and seeing how she was fooled.
- Ice Queen: Lampshaded when the interim election results describe her with "Her cool facade hides a cold vote-grabbing machine!"
- Multi-Ethnic Name: "Miroslava" is a Slavic name, which makes it likely that she isn't fully Japanese.
- Secret Keeper: She finds out that Itsuki hides a crush for Kaede, and whispers to her that she knows and that her secret is safe.
- The Stoic: She always has an apathetic look on her face. Even when she's giving a sadistic glare, the only difference in her facial expression is that there are lots of ominous shadows around her.
- Unwitting Pawn: To Itsuki in the Greater Good Game, as she is basically bribed by Itsuki's own coins to become her accomplice, placing first for most of the game. Thus when Manyuda exposed the traitors, despite Itsuki being the mastermind, the others had to exile her instead because the game is at the last round.
- Villainous Breakdown: Her stoic facade starts to crack when Kaede identifies her as one of the traitors and breaks completely after she's exiled, with her about to go absolutely berserk on Itsuki for setting her up. Fortunately, she then realized Itsuki was a Worthy Opponent, and that combined with her realization that Itsuki had feelings for Kaede & didn't actually play to win led to a case of Defrosting Ice Queen instead.
- When She Smiles: Talking to Itsuki about how Itsuki set things up and why causes Mira to realize she actually enjoyed the gamble. By the end, she can be seen smiling for the first time since her appearance.
Sumika Warakubami / Kawaru Natari
A strange and quiet woman who always hides her face behind a surgical mask and her long hair. She turns out to be a famous Japanese actress in Hollywood under the pseudonym Kawaru Natari, who happens to be Yumemite's favorite actress. Her family branch, the Warakubami, are in the entertainment business.
- Amazing Freaking Grace: Her performance of this old classic brings everyone in the audience to tears and gives Yumemi a lesson that shes not to be trifled with when Yumemi loses in a 92-8 vote blowout.
- Arc Villain: Of the Acting Game, being the main antagonist against Jabami and Yumemite.
- Beauty Mark: Beneath her right eye.
- Connected All Along: That the quiet and mysterious member of the "-bami" family would be a famous actress took Yumemite and basically everyone present by surprise.
- Cuteness Proximity: Erimi triggers this for her, and Sumika would constantly give Erimi all sorts of gifts and toys in the past due to it. It's to the point where she even gave Erimi all her votes because she found Erimi to be so adorable. Erimi meanwhile believes she did so as a sign of trust and faith in her.
- Eerie Pale-Skinned Brunette: She has an almost ghostly look to her appearance, not unlike a Stringy-Haired Ghost Girl. Even after she reveals herself as Kawaru Natari, her looks remain rather... off.
- Foil: She is essentially everything that Yumemite aspires to be as an actress. The entire Acting Game is basically one long description of how far Yumemite is from her dream, seeing how much more talented and experienced Sumika is. It's also lightly implied that she has something that Yumemite lacks in her core.
- Graceful Loser: Once defeated by Yumemite's desperate attempt, she recognizes her own defeat gracefully, as well as the danger of her own overconfidence. She congratulates Yumemite for her win, even if it was a clumsy one, saying that "a win is a win" and "a loss is a loss". She then gracefully says she'll wait for Yumemite in Hollywood.
- Hidden Eyes: They can't be seen beneath her hair. When she reveals herself as Kawaru, they're very wide and rather eerie.
- Hoist by Her Own Petard: Taking advantage of the rift between Yumemite and Jabami, as well as the fact that she can see through their act easily, she raises the pot value to over 63 during their final game, but once Yumemite fully decides that she can't give up, it's clear that Yumemite has also seen through her when she let her guard down and leaves Sumika to fall on her own trap.
- Jerkass Has a Point: She may be unpleasant and freely passive aggressive to Yumemite, but she is right about the little amount of respect that Yumemite seems to put on acting, and how little skill she has.
- Non-Uniform Uniform: She is the sole female member of the academy to wear a knee-length skirt rather than the usually shorter ones.
- She Cleans Up Nicely: From a Stringy-Haired Ghost Girl to a far more dignified and pretty appearance, fitting for an actress.
- Surprisingly Good English: As she's a Hollywood actress, despite being born in Japan, her English is indistinguishable from a person who learned English as their first language. The anime even got Ayahi Takagaki, who is known for her own Surprisingly Good English, to be the voice of Sumika in part for this reason.
A level headed and polite man who showcases an outstanding prowess in bluffing. He comes from a family of swindlers.
- Ambiguous Situation: Born from his lying and deceiving nature, whether Ibara's devotion for him is reciprocated. It's unclear whether Rin sees Ibara as a useful minion or a true friend he wishes to help and protect. It's revealed to be the latter, although Rin's so accustomed to lying that he can't express it in any truthful way. At best, all he could do was a Be Cruel To Be Kind and kicked Ibara out of the clan when he decided a liar like himself was doomed to be alone. Ririka saw right through it.
- Animal Motif: Storks, which are used to represent his family.
- Bitch in Sheep's Clothing: Despite being outwardly nice and kind, Rin is quite manipulative and downright nasty at times. Ibara's devotion for him comes with a constant anxiety that he might someday get stabbed in the back by Rin.
- The Charmer: He uses his charm with female students in order to get help. He seduced and manipulated Saotome's three friends into thinking each of them had a conspiracy with him during the War game. In truth, he was using all of them to make sure that, no matter how complicated the game would get, he could use the three of them to make sure that he and Ibara were safe.
- Childhood Friend: With Ibara. After Ibara became the family's punching bag for his incapacity to lie, Rin incorporated his honesty in his own swindling and gave him a hope of escaping their life.
- Consummate Liar: As part of his swindling, he is a master liar. He is able not only to lie to others, but actively manipulate them into lying for him to others or take risks they shouldn't, which is how he plays Ririka, Ibara and others in the War game.
- Crazy-Prepared: The War game turned out to have various fail-safes to make sure that Rin would be ok no matter the outcome of the game. He set up three participants to lose if the game became too bad for him and Ibari, as well as having a fake referee for the entire game, making sure that if the thing really hit the fan, he'd still never really have to pay the votes he'd own since the match wasn't official. He is still Out-Gambitted by Ririka regardless, who says that if he really wanted to win no matter what, he should have tweaked with the system of the game.
- Cry Cute: For a male character, Rin looks unusually nice and adorable when crying at the end of the War Game.
- Exact Words: Part of his manipulations rely on him saying things that are true and that lead other people into thinking other things are true based on that when they aren't necessarily connected. During the war game, he mentioned that there was no unified conspiracy, which was indeed true. Because there the conspiracy in question wasn't unified.Rin: "There's no unified conspiracy", "I didn't sent a request to Ibara". I don't think I've told a single lie here, have I?
- Eyes Always Closed: He usually keeps his eyes closed, though he opens them when surprised.
- Idiot Hair: Downplayed, the hair isn't coming out of the top of his head, but of the right. Fully subverted as he also displays signs of being a very smart person.
- Inferiority Superiority Complex: His pridefulness comes from a vicious anger at Kirari for humiliating him when they were kids and the fact she's been looking down on him ever since. He deals with this by obsessively finding people to look down upon himself while trying to find a way to defeat Kirari.
- Manipulative Bastard: Rin is a prodigy in a family of swindlers that has been lying, manipulating and toying with people since childhood, with the only possible exception being Ibara. He gleefully starts a virtual coin scheme in the school during the elections to make sure he would get several votes before others realize that he would devaluate the coin by the end of the election. He also manipulated and charmed three girls into being scapegoats during the war game, making each of them believe they were part of a conspiracy with him, when the actual conspiracy was to make them a safeguard for himself and Ibara if things went south.
- Oh, Crap!: Rin is so sure in his plans that the rare moments where things go south, he can't help but show it in his face. He gives a particularly noticeable one when Ririka shows that she has figured out his lies and manipulations by revealing his plans to the girls he was going to use as scapegoats. Kirari easily noticed the same thing when they were children..
- Out-Gambitted: His final fail-safe for the War game: to reveal that the referee of the game was fake and therefore the game was null and void, is called out by Ririka, who predicting something like this, called Runa and kept her on the line during the duration of the game, therefore making it so that an actual referee was overseeing the game all along from her phone.
- The One Guy: Downplayed, he is not the only male member sent to the academy, since Ibara came with him, but Ibara is only there as his support, making Rin the only male member of the Devouring Families actually taking part in the competition.
- Pretty Boy: Rin has very good looks and actively uses them in his manipulations when he has to involve some other females in it.
- Pride: To the point where he has an unhealthy and obsessive desire to look down on everyone and can't stand it when someone is looking down on him instead.
- Red Oni, Blue Oni: The levelheaded and polite blue oni to Ibara's rambunctious and loud Red Oni.
- Take a Third Option: When Kirari traps him and Sumika in a game of poker where she keeps going all in and neither of the others are willing to take the bet, he simply leaves the game, rather than keep letting her get his votes one by one, which surprises even Kirari.
- Villainous Breakdown: Gets a really hard one after the end of the War Game, but is brought back with the support of Ibara.
A rebellious uncouth punk who is a member of the Obami clan. While Rin Obami is the chosen representative of the Obami clan, Ibara is accompanying him and participating in the alliance against Kirari as well.
- Because You Were Nice to Me: His loyalty to Rin comes from the fact that Rin was the only one to ever show him kindness in their family, after he found himself unable to lie in a family of swindlers.
- Boisterous Bruiser: He's fast to confront others and mock them, but that brash confrontational personality becomes this when he's in a good mood, such as when he mistakenly believed Yumeko was recruited to their cause to take down Kirari and happily proclaimed they could take her down together. Once victory in the Greater Good game was set for everyone (besides one of the traitors), he energetically acted really friendly to everyone and even tried to give Kaede a high five.
- Butt-Monkey: Because he's so brash and rude to everyone, he initially seems like a Smug Snake that ends up breaking down more and more over his possible loss during the Greater Good game. At first it's unknown if he's just pretending to hide that he's the traitor, but in the end, he wasn't the traitor after all and his previous breakdown was genuine. The remainder of the game basically has Kaede playfully making fun of him in various ways, although he did get 2nd place (tied with Yumeko) in the end so he came out alright.
- It turns out he's physically unable to lie in a family whose business revolves around subterfuge and lying. The poor guy was a Butt-Monkey to the entire family until Rin found a use for him. And even then he always had to wonder if Rin was just using him, too.
- Cannot Tell a Lie: His strongest and most dominant trait as his unwillingness of lying is so severe that he's in fact physically incapable of doing so and needs help by other members in the family to even commit a convincing swindle. In anyone else, it would be a great virtue, however, being born in a family composed by nothing but swindlers and shameless liars, it becomes a vice and makes him the Black Sheep of the family by default. Paradoxically, at the end of the war game he is considered a liar by saying he is also a liar
- Childhood Friend: To Rin, being extremely devoted to him for being the only nice person to him in their family. While he likes and respects Rin a lot, he hides a lot of anxiety on whether or not he is being just used by Rin, but desperately believes that he is looking out for him as a consolation. Interestingly, while he's not sure whether or not Rin's just using him, he's aware that Rin at the very least looks down on him but doesn't mind. In fact, he's actually worried about Rin because Rin seems to have an obsessive need to look down on EVERYONE.
- To Mira, who's The Stoic while Ibara is extremely passionate and rude. Lampshaded when the two realize that their match is a chance to take Yumeko's votes. Despite the inner narrative showing they both feel that Yumeko and Itsuki's votes are "ripe for the picking", Ibara has an Ax-Crazy Slasher Smile while Mira has her same apathetic expression except the lighting and the angle makes it look more ferocious.
- To Rin Obami as well. Rin's eyes are always closed with a serene look while Ibara's are wide-open and manic, and the two are introduced together with Ibara jokingly giving the calm Rin some bunny ears behind his back. Ibara has messy blond hair while Rin's hair is black and combed. You wouldn't be able to tell they're from the same family clan by looking at them in the present day. Personality-wise, Ibara is outwardly a guy with a bad boy vibe while Rin is pretty and proper, but whereas Ibara is a Nice Guy deep down, Rin is a Bitch in Sheep's Clothing.
- Nice Guy: Considerably nicer than he appears to be and even more so when compared to the other members of The Clan. He goes along with Jabami's plans and even tries to befriend Kaede, though to no result.
- Non-Uniform Uniform: His uniform is wore much more laidback than any other male character. The top of his shirt is unbuttoned, his tie is loose, and the sleeves of both his arms and pants are folded, showing his arms and knees.
A member of the Komabami family, who is always being accompanied by a dog. She seems to be looked down upon by the rest of the families.
- Big Ol' Eyebrows: Her eyebrows are her most noticeable physical feature.
- The Dog Bites Back: One of the reasons she was so willing to betray Rin and join Ririka was because Rin always looks down on her.
- The Generic Guy: She has the least assuming appearance of all the Hundred Devouring Families' members seen.
- Naïve Animal Lover: She seems innocent and brings her dog with her, though it is in comparison to the Hundred Devouring Families and her family might be related to pets.
- Skirt over Slacks: She wears shorts under her skirt, which are pretty noticeable.
An anime-only character. She acts rather like a butler for the other members of the Momobami clan and arranges matches for them, but doesn't take part in gambling herself.
- Bifauxnen: She's female, but she wears pants with her uniform, has an androgynous appearance, and speaks with a deep voice. She adopts a more feminine look when she reveals who she really is. Her clothes follow along after her final gamble with Yumeko.
- Canon Foreigner: Created specifically for the anime's second season. Interestingly enough it was implied at the end of the season that it was Yumeko's older sister losing a Clan Gamble that set Rei down the path she goes.
- Dull Eyes of Unhappiness: Her eyes are lightless and black, reflecting her general lack of goals.
- The Charmer: Convinces two girls to stop bullying another with just her charm.
- Conspicuous Gloves: Unlike Miroslava's black gloves, she wears white gloves to go with her butler image. They also hide the tattoos on the back of her hand that give away her identity.
- Final Boss: Of season 2. She is the final gambler fighting against Yumeko and the Devouring Families themselves.
- Keigo: Her speech patterns are very formal, to the point that she refers to herself with the extremely polite "watakushi" pronoun.
- Meganekko: The only member of the Hundred families so far who wears glasses.
- Meaningful Name: Her last name is pronounced "Punishment Eater" and spelled "x喰"/"X eater", reflecting her identity as a member of the Momobami clan who was stripped of her name and exiled. Her first name is also the character for "nothing", reinforcing her overall identity as a character who lost everything and went from a member of a powerful distinguished extended family to a mere servant.
- Non-Uniform Uniform: She wears pants with her uniform despite being female, which adds to her Bifauxnen image.
- Not So Stoic: She usually keeps a composed demeanor, but there are two moments where it breaks.
- The first is during the Greater Good Game when Yumeko admits that she feels guilty about not feeling guilty for ruining other people's lives through gambling. This answer makes Rei fly into a rage. Considering her backstory, it makes sense as to why she's angry about Yumeko's response.
- The second is when she notices Yumeko's strange bidding behavior during the auction. She is clearly caught off guard and fails to understand what gambit Yumeko is trying to pull off. This leads directly into her Villainous Breakdown.
- Pet the Dog: After undergoing an insane gambit against Yumeko in the Auction Bidding game with everything on the line in the spirit of a true gamble, Kirari grants her the rights of having a official family name once again and the rights of a official bloodline within the Hundred Devouring Families once more.
- Villainous Breakdown: As soon as Yumeko puts her full plan during the auction into action, Rei progressively starts losing her cool as she watches her votes quickly depleting right before her eyes.
- Wild Card: According to Kirari, she's not going to help either her nor the other members.