a.k.a. Konjiki no Gash Bell!!, or Konjiki no Gash!!A manga created by Makoto Raiku. This series is a very unusual take on the Mon genre, in that the "mons" of this series are for the most part, super powered children with a human "owner". One hundred demon children (mamono in the original Japanese, called "mamodo" in the English release) are sent to earth to do battle with each other to find out who will be the next generation's King of Demons. The catch is that they can only use their demon powers if they find a human to read spells out of their book. If their book is burned, they're banished back to the demon world and are out of the contest.The show specifically features the adventures of the arrogant Japanese junior high school student, Kiyomaro Takamine (shortened to "Kiyo" in the English release), and his hyperactive mamono partner, Gash Bell (renamed "Zatch"). Together they decide to try to make Gash the Demon King, so he can rule over the demon world with kindness.The series ran for 33 volumes and was adapted into a 150 episode anime.
More in the end Zeno, Zatch's twin brother, falls in this after realizing his father hadn't give him the supreme power of Bao because he feared his bloodlust and ruthless would lead to his own demise when he tried to use it. Also the memories Zeno stole from Zatch helped him see his "stupid civilian" life wasn't only happiness and innocence as he thought it was and Zatch wanted badly to meet his brother.
All Your Powers Combined: Zatch's golden spellbook contains the strongest spells of most mamodo in the fight, for Kiyo to use freely. This is used to defeat Clear Note at the end of the manga.
Another example comes from The first Movie, with the 101st book. Used by Wiseman in a ploy to get himself in the battle for king, it STEALS spells from other books and uses them as its own. Ironically, something like this would have been useful against Clear Note as it was made as a precaution to stop crazed king candidates, but you know how movies and canon work out together. Anyway, his scheme was neutralized when Gash, Tio, Kanchomé, and Umagon were able to unify their powers into one spell, which burned the book.
When he and Kiyo first meet, the manga flat out tells us there's no language barrier between them.
Well, Kiyo's main allies are all well-educated/well-traveled, and it's not impossible that they'd be able to speak multiple languages, or at least be speaking English some of the time. Also something to remember is that Kiyo himself is a genius so much so that he was able to teach himself how to read the language of the demon world and reprogram a computer enough to make it virtually unhackable in less than an hour, so its not a stretch to say that he knows more than one language.
Anyone Can Die: That is, having your book burnt and returning to the mamodo world, which frequently happened even to sympathetic characters.
Thanks to the nature of the central conflict, we learn very early on that this is going to happen to EVERY demon child character in the series, except one. Naturally, every demon child is competing to be that one. It's an unusually dark setup when you consider how light-hearted the series usually is.
Wonrei and Kido are probably the best examples.
And towards the end of the manga once the battle comes down to the final ten, Zatch's friends (who've pretty much been there since the start) begin to get picked off one by one until Zatch, Brago and Clear Note are the only ones left.
Anti-Climax: The revelation of Arth's final spell. It had been hinted at for an arc without actually showing up, with Arth finally using it in his battle against Gorm. He casts it, and hundreds upon hundreds of BFS's rain from the sky. You'd think Gorm would be screwed, right? Nope. He promptly pulls out his ultimate spell, which summons as many black holes as Arth has swords, and the black holes suck up the swords like nothing. Arth doesn't last long after this.
Anti-Villain : Barring a few exceptions, most demons Zatch and his friends fight are not truly evil, and several express regret for their actions.
Apologetic Attacker: Kolulu and Lori are forced to fight Zatch and Kiyo when Kolulu transforms into her brainwashed form, and tries to stop the attack.
Armor-Piercing Question: "What kind of King do you strive to become?", from Gustav to Bari. This, together with Zatch's own goal of "Becoming a Kind King" make Bari rethink his way of fighting and define his own goal of "Becoming a Strong King".
Art Shift: When ever someone is playing the Only Sane Man or the Straight Man they get drawn in a very blocky style. Kiyo will sometimes go entire chapters with this face in front of the astounding weirdness of this series.
Attack Reflector: Spells like Rashield and Ma Seshield can actually reflect the opponent's attacks.
Notable in that, for (eventually) all three, this is elevated to the level of a literal superpower, "Answer Talker" for Kiyo and Dufort and an unspecified precognitive ability for Apollo.
Badass Adorable: Most of the smaller mamodo qualify for this. Examples include Zatch, Tia, Kanchome, Ponygon, Laila, Penny, and the list goes on...
Doctor Riddles and Kido also apply. The first doubles as a Badass Grandpa, the second is a little glasses-wearing demon full of curiosity who can shoot giant-sized rocket punches.
Badass Normal: Sherry is more badass than most males, has a cool weapon and generally kicks more ass than more or less every other human in the series.
Well, her name is Sherry Belmont. Hell, she even has a whip.
Parco Folgore also applies, especially when he protects Goomu and Mir from receiving a major punch from Kanchome after he goes ultimately insane with Shin Poruku.
Nearly all the recurring book masters apply. As targeting a demon book directly is, perhaps, the most common tactics in this manga and, moreover, villains are generally fine with torching masters alongside with books, all human good guys need to be able to dodge death beams and survive being thrown around by explosions. Besides those mentioned above, worthy of special mention are Dufort and Apollo, whose abilities are precognition in all but name, as well as Gensou, who decided to accept his book, because he found human martial artists too boring.
Bait-and-Switch Boss: Riou, defeated by Zeno. Subverted in that he badly beats Zatch and Kiyo before he goes.
Back from the Dead - In the manga Kiyo after Riou beat the living shit of him while he was preparing the most powerful attack, Zatch in despair resurrected him, accidentally.
Big Eater: Most of the mamodo LOVE yellowtail fish, and actively search for them, and eat them whole.
Bittersweet Ending: Gash becomes the Mamono King. But since the way to the human world is closed. It's possible that Gash and Kiyomaro will never see each other again (made worse by the fact that Gash will most likely outlive Kiyomaro.
Bowdlerize: Zatch is given boxers in the English dub while he had nothing under his cloak in the original.
He actually does wear boxers under his cloak in the Japanese version of both the anime and manga, but the English version of the first manga chapter ends up showing Gash putting boxers on over ANOTHER pair of boxers. Meanwhile, the dub of the first episode cuts out a scene of Kiyo accidentally getting a close look Zatch's naked crotch before screaming and falling over in shock.
Folgore's song about breasts, "Chichi o Moge".
Everything about Big Boin and her "Boin Chop". Strangely, when Kido and Zatch doing it is not censored.
The above cuts were even done in the US manga, for whatever reason.
Viz tends to do this whenever they have an anime adaptation, so they try to make the edits emulate what happens in the animation. Never mind the fact that one of the characters insults Kiyomaro by calling him "Piyomaru" in the English dub, even though he's called "Kiyo" in that dub.
Beware the Nice Ones: Don't piss off Zatch, you will regret that. Or for that matter Kiyo. You know what; especially Kiyo.
Kanchome is cowardly and childish, BUT FOR THE LOVE OF GOD DON'T PUSH HIM TO THE EDGE!
Rein, despite his intimidating appearance, is easily one of the nicest mamodo. Of course, once his friends and especially his book keeper are threatened, he shows he gives new meaning to the phrase "scary strong".
BFG: Cherish's rifle spell,and her Shin Level spell has mini-drones that support fire.
BFS: Arth's upper tier Spells,and his Shin Level spell is RAINING BFS's
Big Bad: Each of the three major story arcs have one: Zofis in the Ancient Mamodo arc, Zeno in the Faudo arc, and Clear Note in the King Festival arc.
Big Damn Heroes: Happens in a lot of the bigger battles, but it hits its peak when Clear looks like he's going to defeat Zatch and Brago, the last two Mamodo on the planet besides himself. Who comes to save them? All of the already defeated Mamodo!
Bittersweet Ending: Zatch becomes the demon king, but has to go back to the mamodo world. Worse, the way to the human world for demons is closed, so Zatch and Kiyo will never see each other again. Hell, this also applies for most of the human and demon teams. They grow attached to each other, but their books are burned and they never see each other again.
Somewhat negated due to the fact that Zatch manages to send Kiyo a letter promising that they will meet again.
However, there is also the fact that Kiyo learns that Suzy and all of his friends were sent to different schools, implying that probably they are never going to see each other again.
Blood Knight: Bari starts out like this, but eventually gains ambition beyond simply beating people up after his encounter with Gash. Also, Kolulu's second personality (see below).
Brago begins as this as well. Plus, a bunch of lesser characters qualify too.
Brainwashed and Crazy: Because of her pacifistic nature, Kolulu was saddled with a second, MUCH more violent personality that manifested whenever her spells were cast in order to ensure her participation in the battle for kingship. However, she is the only demon who appears to have undergone this treatment, despite there being a few more demons (Rein comes to mind, as well as Momon in his first appearance) who have no interest in fighting, even for the side of good.
There's also Koko, who turned sadistic and mean-spirited under the influence of Zofis.
To be fair to the interests of the plot, not everyone stops to tell the audience they're brainwashed before their book gets burnt.
The dog demon from early on starts whining when his book master shows up at Kiyo's house, suggesting he also was controlled.
The big group picture of all the mamodo at the end, who appear to be getting along, would suggest that Kolulu's story has truth to it, although she's the only one whose alternate personality took a different physical form.
Breath Weapon: There's a subset of Mamodo who have these. For example, Zatch's most basic lightning spell, Zaker, shoots lightning from his mouth.
Later subverted with Cherish for Ted, due of the fact that Cherish was being manipulated by Riou, and later by Zeno.
Cain and Abel: Zatch and Zeno. In the childhood friend variety, Sherry and Koko.
Calling Your Attacks: Played with somewhat: attacks ARE called, but the people that do the calling AREN'T the ones that perform the attacks.
Came Back Strong: Kiyo dies or comes very close to it in Faudo, and when he reawakens his heart power is massively increased and he gained the answer talker ability.
Canon Immigrant: The wind Mamodo, Hyde, who Zatch fought in filler segments at the very beginning of the anime, appears multiple times in the end of the manga.
Captain Ersatz: Some of the Majestic Twelve are based on American superheroes; Two-Lightning Eye is clearly based on Cyclops of the X-Men, while Rocket Foot is obviously inspired by the Flash.
Cartesian Karma: Tacitly averted with Koko who was sadistically brainwashed, but is later rescued by Sherry and restored back to her original, kind innocent state. It's a good thing she's not a wanted criminal now or anything and can happily go to college too, especially after (publicly) razing most of her town and kidnapping dozens of people. It would have to be inferred that her savior Sherry has some pretty good connections.
Victoream: "Very shit!" (only in the original version, of course)
Character Development: There are lots, especially for the demons. Special mentions goes for Kanchome, Brago, and last but not least, Zatch.
One can track Zatch's growth via his eyes.
Significant growth is what lets demons gain new spells.
Characterization Marches On: Sure, Kane just grew out of his bully phase, but the sadistic way in which he behaved in the first story is so radically different from how he is for the rest of the series that it really feels like this trope at work.
Chekhov's Gun: Done wonderfully with Zatch's memory which Zeno stole from him after nearly killing Zatch in the beginning of the tournament. During the showdown at Faudo some of memories of Zatch leak and gets to Zeno's making him to see how wrong he was about his hate towards Zatch and after his defeat the entire things gets to him while he's dreaming and definitely making him regret for everything he had done to Zatch.
In an early chapter of the series it is explained that some demon's spell make them go crazy and fight against their will, hundreds of chapters later, in the final arc, Clear Note is one of those demons
Chekhov's Gunman: If a character fights any of the main characters and doesn't have their book burned, expect them to show up roughly a hundred chapters later and either help out the heroes or work for the villain. Except for Baransha. She's just a douche.
Covered with Scars: Bari's look for his last appearance in the manga, courtesy of Elzador, a prodigy of the Dragon Clan
Crouching Moron, Hidden Badass: Several characters qualify, but Byonko practically embodies this trope. He spent nearly 50 chapters playing the role of Butt Monkey, but the instant his spells finally come into play, he starts smacking around one of the strongest demons in the series to great effect.
Kanchome. Just Kanchome.
And Folgore. Good god, Folgore.
Momon as well, once he stopped being scared. In fact this happens with a lot of the Mamodo, except Purio. Heck he almost defeated Rondeux AND Jedun while both fought him at the same freaking time.
Holy crap about anyone who fights Zeno ends up in this.
The very first time Zatch and Brago "fought", that being in quotes because they stood no chance against Brago.
After Kiyo's return, Zatch vs. Rodeux. And how.
Dark and Troubled Past: Suprisingly, Folgore. Before he turned into the cheerful and famous Italian pop star, he used to be a violent delinquent in his hometown. His behavior was so frightening that even made his own parents get afraid of him, turning him into a complete outcast and consequently making him to leave the city.
Apparently, Mir's life before she met Goomu was pretty rough despite the little information that is showed to us in the manga. Her heavily scarred back and intense submissiveness to a stronger power have some seriously unfortunate implications regarding what happened to her. It's actually so bad she has no qualms with attempting to kill Elly with Goomu's Diaborosu Za Randamito, when she is all of six or seven years old and has a serious medical condition.
Brago could be considered pretty borderline evil in the early story. At least somewhere between a Jerk Ass and sociopath without much heroics. He gets better.
Death Glare: A sign that you have truly pissed off a protagonist. Zatch, Kiyo, Brago and Sherry in particular have raised this look to an enemy-halting art-form.
Death Is Cheap: Kiyo dies during the fight in Faudo. It takes about 40 chapters for him to start fighting again, and he even gets powered up for the experience. Then again 40 chapters is a rather large cost.
Deliberate Injury Gambit: Kiyo tries this during his fight with Riou, but in a subversion, he is killed.
Demon Head: Kiyo. This reached epic heights during his Unstoppable Rage against Rodeux in the manga. AND THE ONLY ONE ABLE TO MAKE ZENO TERRIFIED (At least for a few seconds though). Dufort even broke a sweat. (To see this, go to Say My Name)
Determinator: So very many. Includes the ENTIRE main cast, a lot of the side characters, most of the villains, and more than a few one-shot characters. It'd be quicker to list every single person in the story who DIDN'T fall into this category.
What interesting is despite this trope, victory not always certain. Though at the very least the characters are left alive to fight another day.
The Ditz: Suzy. Just to give an example, when she was a kid, she was trying to lead a lost little girl home, only to be distracted by a kitten trapped in a box floating in the river. The two of them ended up several miles away from where they wanted to go.
The Dragon: Demolt to Zofis. Almost literally, since he has a rather draconian appearance and is outright stated to be stronger than Zophise.
Fear of Thunder: Cherish. Being tortured and almost getting reduced to a crisp by a Enfant Terrible will make you get enough trauma so even the lightest of shocks will make you shiver in tears.
Four is Death: Out of all of the Mamodo that Zofis revived from a thousand years ago, the last four are the most powerful.
Also, Zatch's fourth spell is Bao Zakeruga, which is a major plot point in the series.
Freudian Excuse: Why does Zeno hate Zatch? He believed that Zatch was the favorite child, since he received the power of Bao, and Zeno had to go through Training from Hell.
Gag Boobs: Big Boin/Lady Susan IS this trope. And to lesser extend, Wife and Miss Wriggle.
Gentle Giant: Shin. His first appearance includes not only helping Zatch get off the swing sets he's trapped on, he helps and old lady cross the street, sorts the recycling bin, and is nursing an injured bird back to health. Unfortunately, being the gentle giant, his past involves the gigantic kid being bullied back in elementary school, and his mother's dying wish (which apparently happens while he's only a child) is for him to be able to stick up for himself. Naturally, the poor guy has to have a douchebag mamodo who uses his reverence for his mother to try and get him to do things like attack a school. He's a little bit of The Woobie as well.
Rein both subverts this trope and plays it straight at the same time. He used to be a complete savage in the past, and in the present he's got an intimidating and sometimes downright scary appearance, and he's also very powerful when battling. However, he's also very friendly, kind, gentle, and doesn't even want to fight if he doesn't have to.
Getting Crap Past the Radar: Lori's backstory involving neglecting parents is... interesting. The way she feels adopting Kolulu is the only way to fill the hole in her heart is shockingly similar to some teen pregnancy stories, if you replace adopting Kolulu with giving birth.
Suzy's oranges that have faces on them have sometimes cracked open, and the blast of orange juice looks like somebody's head just opened.
A good deal of stuff Suzy does with her fruits count, actually.
Hard Work Hardly Works : Subverted, Zeno achieved his power through rigorous terning and is one of the most powerful demons. Just to sum up he beat the living shit of Leo, the mamodo who actually did kill Kiyo (he got better), even after his Dangerous Forbidden Technique which was supposed to increase his power by ten times.
Koko also gets one at the end of the Ancient Mamodo arc, though that's more because of her Laser-Guided Amnesia that sets her back to how she was before Zofis gave her a Face Heel Turn.
Heel Realization: Zeno during his battle with Zatch in the manga. Turns out his grudge against him was purely out of jealousy with what he assumed Zatch having an easy life while he was put through a Training from Hell in the demon world. However he find out this wasn't the case and later repents for his actions.
Heroic Sacrifice: Not the death kind, but moreover letting the books burn to save someone. Gets especially frequent during the Clear Note arc.
In the manga, when Zatch fought with Riou, Kiyo lets all of Riou's spells hits him and actually died. He tried to ensure Riou's defeat to save Japan while protecting Zatch's book, his last thought was for Zatch to become king with his new partner.
I Let Gwen Stacy Die: Lori's partner Kolulu gets her book burned due to being Brainwashed and Crazy, and gives Zatch the idea of becoming a kind king, whereas he and Kiyo were simply fighting for their right to stay together before. Whenever Zatch reaffirms his purpose, a brief flashback to that scene is likely not far behind.
Image Song: The duets were to be expected, and some of the side characters get their share.
Ineffectual Sympathetic Villain: Purio. While he isn't completely useless in battle (see Not-So-Harmless Villain below), he's still regarded as a nuisance by most other demons and makes it to the final ten by sheer dumb luck.
Instant Armor: Lots of spells do this. Their weight is never commented on, so the spells probably increase strength as well.
Interspecies Romance: Between Wonrei and his bookkeeper, Li-en. But Wonlei resembles an adult human closely enough for it to be OK.
Obviously, the relationship doesn't last, as eventually Wonrei's book is burnt.
Insufferable Genius: Played with - Kiyo starts out despising his intellectual inferiors (read: everybody) and the feeling's mutual. On the other hand, his unpopularity actually seems to bother him a lot and it might be a chicken-and-the-egg situation because they were jealous.
Involuntary Battle to the Death: The entire mamodo battle becomes this for some of the more peaceful mamodo. Kolulu mentions that these mamodo are implanted with an alternate, more violent personality so they are forced to compete.
Jerk with a Heart of Gold: Parco Folgore, a Handsome Lech pop star who spends most of his time chasing after bambinas. Oh, and he's also really devoted to his patheticaly underpowered demon partner, Kanchome.
Also Kiyo, who doesn't appear to have any redeeming qualities when we first see him and still has some real jerkass moments.
Naomi could count as well. Even if she tortures Zatch whenever they meet, there still instances where she not as bad as she seems (i.e. Saving Zatch on one occasion and cleaning the playground when it's left a mess.)
Jive Turkey: Kafk Sunbeam is positively groovy, bruv.
Kangaroo Court: Referenced by name in the episode where Zatch is sick.
Karma Houdini: Nearly every villain either changes sides or gets their comeuppance eventually, with the notable exception of Robert Vile, Zofis's Evil Genius, who runs away in terror upon his demon being defeated and the heroes decide not to pursue him for some reason.
Keet: Just look at that image and say that doesn't 100% apply to Zatch.
Knight in Shining Armor: Arth, who both employs iaijutsu and is an animated suit of Shining Armor.
Large Ham: Victoream. From his uber-serious voice (courtesy of the king of all scenery-chewing in anime) to his constant showboating to an extended song and dance number about how much he enjoyed eating a melon, he's tremendously entertaining and a little hard to take seriously until he starts shooting huge, V-shaped lasers at you.
Laser-Guided Amnesia: Zeno steals all of Zatch's memories shortly before Zatch is found by Kiyo's father. While Zatch regains his limited memories of Earth when he revisits the spot where they were stolen, the rest of them have to be returned by Zeno after the latter's redemption.
Market-Based Title: The show and titular character were renamed "Zatch" as Viz thought "Gash" was too similar to a slang term for female genitalia. Or a gaping wound.
Meaningful Name: Apollo has the ability to know things before they happen, he can fortell them. The greek god apollo was God of the Sun and Divination. Also Apollo's family crest is a sun
Mind-Control Eyes: Used more often as a Facefault than to actually show that someone is mind controlled, although Koko also has these eyes.
Mirror Boss: A non-Videogame example. When Zatch fights Zeno, being from the same family, they possess the Lighning element and some same spells, and their book owners Kiyo and Dufort both have the Answer-Talker ability, but both Zeno and Dufort have a nasty advantage against them due to years of intense training, BOTH OF THEM.
More Dakka: The Ganzu-type spells involve firing gattling gun like pojectiles of the user's element.
Most Common Superpower: Now, either Big Boing's tremendous breasts are a parody of this trend in American comics, or it's just because she's Foreign Fanservice and meant to be stereotypically American.
Never Say "Die": Justified; demons who lose the battle are returned to the demon world instead of killed. It is implied that they can die in certain circumstances, but since this is an idealistic show, that never happens.
Late Manga Spoilers: Somewhat subverted later in the manga, when it's revealed that the entire population of the demon world, including those who were sent back in the battle essentially are dead. They've been reduced to a spirit form until the winner is crowned, upon which the king can choose to either revive whoever they'd like, or instead remove them from existence.
Not So Harmless Villains: Purio and Zoboron turned out to be a genuine threat when working in tandem, despite being seriously goofy no matter how you look at it.
This happens with Purio and Rodeux much later, though Rodeux is more than threatening on his own.
Ironically, when you take a look at Purio's spells, you realize just how much potential he had. His spells mainly consist of ways to incapacitate the opponent (both the mamodo and the book owners), namely slippery liquid, sticky liquid, paralyzing liquid, a potent itching powder, a very tough net, and a smokescreen they used for quick escapes. His single offensive attacks? He spits freaking acid! With that set of powers, he could have easily been a front runner in the battle, but the immaturity and goofyness of both him and his book owner cause them to be a weak team on their lonesome.
Omnicidal Maniac: Clear Note, who tells straight up that his only goal is to eliminate demons, and even compares himself to the atomic bomb during his introductory fight.
Panty Shot: Suzy's skirt lifts up when Zatch uses Zaker for a second time in Episode 1.
Happens a couple of times with Tia and Penny too.
Personality Powers: Spells are intimately tied to Character Development, so it was fairly obvious; brash and outgoing Zatch has lightning, Small Name, Big Ego wannabe Kanchome has illusion powers, and so on. Taken to an extreme with pervert Momon, who has a moveset entirely based on skirt-flipping and running away. There's also Tia, who gets mostly healing and defensive spells, which is her true nature. However, she also has a spell that makes it quite clear that pressing her Berserk Button is a VERY BAD IDEA.
Pet the Dog: Surprisingly Rodeux, of all people, when he met Cheeta.
Power of Friendship: In spades, going above and beyond usual Mon fare. Desire to help/protect/save their friends serves as the main motivation for most of the good guys (except for one or two pairs that implied or just about outright stated to have romantic relationships) and inevitably gives them Heroic Willpower to go on.
Pragmatic Adaptation: "Tio" is not a girl's name is most non-japanese languages.
Pure Awesomeness: Various times during his fight with Bari, Zatch is able to stop him just with the intensity of his glare. Actually becomes a plot point when Bari fights Keith and it's revealed that if one is awesome enough he gets "strong eyes" which effectively makes one badass incarnate.
"The Reason You Suck" Speech: Brago gives a really badass one to Zofis, explaining how at the end Zofis is simply a miserable coward who runs from those he fears.
Sitcom Arch-Nemesis: Naomi, the little girl who always picks on Zatch. It's so bad that when Raidou playing an electronic game in an omake chapter, Zatch's strongest spell, Bao Zakeruga, had NO EFFECT on her.
Small Girl, Big Gun: Cherish. It's shown towards the end that if she had stayed in the tournament longer, her Shin-level spell would have been an even bigger gun.
Small Name, Big Ego: Victoreem. Oh, sure, he's strong, and everything, but no amount of ability could possibly back up that ego.
There's also Kanchome. And Keith. And Mars. And Fein. And Eshros. And... hell, anyone Zatch fought in the first episodes.
Robnos takes if pretty far, too, constantly insisting that he has the upper hand and even calling himself invincible.
Not So Stoic: She starts to show emotions After Zatch convinces her that she can trust him and in his friends, and when her partner Albert shows that he deeply cares about her, even when mind controlled.
Super Mode: Zatch's Rauzaruk spell increases his fighting power.
Super Strength: Most of the mamodo in the battle are gifted with this.
Talking to Himself: The dub was cancelled before the Faudo arc, so this is averted for Zatch and Zeno.
There Can Be Only One: Only one gets to be king. Cooperation is gained through promises of power, admiration, or making sure that the only people in the finals are the ones that share your vision.
The Starscream: Pretty much all of the demons working to unlock Faudo under Riou, and later, Zeno. Rodeux is the only one who sticks around long enough to mutiny, though.
Tomato Surprise: Zeno's relationship to Zatch is kept hidden until near the end.
Took a Level in Badass: Sherry was pretty badass to begin with, but she was still human (which showed on long journeys with Brago when she got tired and occasionally passed out from exhaustion). But right around the time Zofis's castle was being attacked, she started displaying very impressive abilities, such as dodging high-level attacks on her own. So it's more like she already had levels in Badass and then took a few more.
There's also Folgore and Kanchome, who take steady steps towards Bad Ass status in the course of the story. A highlight are the chapters focused on them, where Kanchome stands to protect a little girl from a Bowser-sized dragon demon. The thing is, he's pissing himself with fear, and is very aware he's asking for an asskicking, but he simply is determined in protecting that girl and "making her smile again". You gotta admit that's a pretty big change from the full-coward and selfish Kanchome he was in his first appearances.
Unstoppable Rage: After having his ass handed to him by Kiyo, Rodeux makes the mistake of berating Kiyo's fallen and incapacitated friends. Kiyo proceeds to hammer Rodeux's defenseless body with spell after spell in a manner that comes uncomfortably close to torture, stopping only to upgrade his Demon Head into progressively more inhuman forms. Amazingly, Rodeux actually survives this.
There's also Tia's Chajiru Saifodon spell, which is literally fueled with Unstoppable Rage. The spell is otherwise useless, making it double as Awesome, but Impractical.
The Unfavorite: Zeno feels he was one turns out he was wrong. Their parents loved them both equally.
Verbal Tic: Zatch comes to end almost all his sentences with "na(ru) no da?" (isn't it so?). He also uses the phrase "Unu!" to express approval, which Zeno later reveals to be a symbol of his knowledge of his relationship to the current King.
Villainous Breakdown: Maruss experiences this when Zatch (who had had bullied in the past) not only holds his own but delivers an asskicking, and Zofis experiences this after Brago tells Zofis why he sucks: he's a simpering coward and threatens to personally make Zofis's life a living hell for all eternity unless he backs down.
What Kind of Lame Power Is Heart, Anyway?: Some of the mamodo get stuck with lame powers. Until late in the series, Kanchome's abilities revolve around transforming for various purposes, but are rarely useful in battle. Purio has the power of snot, which is only mildly useful. Momon has what Kiyo calls "running away powers", which involve running away.
Heart Is An Awesome Power: Later in the series, these mamodo discover useful ways to use their powers. Kanchome, in particular, becomes possibly the strongest mamodo in the series. Momon also uses them to take a peek at Tia's panties...
Widget Series: The premise itself is a straight-forward There Can Only Be One set up but what happens between that is weird. Exhibit A: The Berry Melon Song.
With Great Power Comes Great Insanity: Many bookkeepers let the power of their demons go to their heads. Kiyo is surprised when he finds out that there are exceptions to this rule.
A more notable example is used in the final arc: while training the main characters to improve themselves so they can combat Clear Note, Dufort explains to Folgore that Kanchome holds the most powerful spell of the entire group, the Shin Poruku. However, if Kanchome doesn't have control of this ability, bad things are going to happen. Turns out Dufort was right: During his fight with Goomu, the Shin Poruku makes Kanchome go to his head, turning into an overpowered monster that shows no regret to cruelly hurt Goomu and his bookpartner Mir.
Not that they didn't deserve it but still, he nearly went overboard.
Yandere: Penny quickly turns into this after finally meeting up with Zatch.