On Kiyo's fourteenth birthday, a naked child crashes through his window, riding an eagle with a tuna on his back (no, we're serious). Zatch Bell is an amnesiac child with a red spell book, and one of one hundred contenders in a tournament to decide the king of the demon world for the next thousand years.
All Your Powers Combined: Against Clear's final form, his book turns golden and all the defeated demons show up to lend their support, and in several cases, their spells. Saying it's awesome is an understatement.
Boring Invincible Hero: A surprising subversion. He actually loses several times. First to Zeon (before he met Kiyo), then to Brago, then Bari, and finally Riou. And even then, the victories he does get aren't easy and Kyo and he don't come out unscathed, heck a few time they're nearly beaten to the brink of death.
Super Mode: Rauzaruk, the sixth spell, enhances Zatch's strength and speed exponentially for thirty seconds.At the cost of not being able to use any other spells. Thankfully Kiyo figured this out pretty quickly. The Golden Book in the final chapters, which allowed Gash/Zatch to use souped-up spells of past mamodo who were already defeated.
Super Strength: True of all demons, but most obvious with Zatch, who stopped Pamoon's strongest spell with his body alone.
Death Is Cheap: A subversion, in that he is in fact dead for a short period, only has his heart restarted by an emotionally broken Zatch pounding on his chest, and even that isn't enough. It also takes a lot of Saifogeos and a long dip in restorative Faudo juice before he wakes up, and his allies take a lot of damage by then.
Master of Illusion: Particularly his final spell, which traps the target in a full illusionary world with no escape.
Me's a Crowd: The fourth spell, "Dima Buruk," produces a number of Kanchome clones, each with comparable speed and strength to a Rauzaruk-enhanced Zatch.
Oddball Doppelganger: He can transform into replicas of other charecters, but they're far from perfect. One had a nose that would make Cyrano De Bergerac feel normal and another has a forehead as big as the torso, luckily for him the people he had to fool were idiots
What Kind of Lame Power Is Heart, Anyway?: Compared to Zatch's electrical powers, Tia's shielding and healing abilities, and Ponygon's super-speed armor, transforming into something without any boost to strength seems a bit lame.
Heart Is an Awesome Power: Of course, once you figure out how to use these powers correctly, they're useful. Kanchome's illusions are vital to a number of victories, and once he develops stronger techniques, is arguably the strongest demon in the series.
My Name Is Not Durwood: He keeps trying to tell everyone his name is Schneider, but nobody understands him. Once they are back to the demon world, he has grown fond of the Umagon/Ponygon name, even though everyone already knows his real name.
Continuity Nod: In a breather chapter, everyone is trying to learn to ice skate, but all fail spectacularly. Sunbeam is especially livid banging and cursing the ice (as it wasn't that much later from his fight against Sauza and Karudio.
Friend to All Living Things: Animals love him, and he can understand their thoughts. The epilogue shows him living on an African animal sanctuary.
Interrupted Suicide: As a little girl, she couldn't take her mother's abuse and attempted to drown herself, but Koko saved her.
Jerk with a Heart of Gold: Spares Zatch and Kiyo the first time because she ultimately feels that they share a similar motivation (trying to save their friend) and by tearing friends apart, she'd be no better than Zofis.
Faux Action Girl: Wonrei normally does the fighting, after all, and the one time she gets to blows with an antagonist she's quickly taken down, despite supposedly being skilled in martial arts herself.
Beware the Silly Ones: In the Faudo Arc's final battle, he beats Rodeaux, Zeon's incredibly deadly Dragon, to a pulp using nothing but support-type spells. He's in control the entire fight, and only loses because Rodeaux takes a cheap shot at Elle.
My Greatest Failure: The reason he was sitting around doing nothing? He used to be a surgeon. Then he failed to save a child, and the guilt drove him into seclusion. In the original, the child's also his grandson.
Heel-Face Turn: In his backstory. He was originally a violent, rampaging demon who was feared and hated. Once, he severely injured himself, and despite his threats, Zatch brought him back from the brink of death. Afterward, Rein reformed.
Initially presented as opponents to Ponygon, they later join the heroes to fight the Faudo cultists.
An Ice Person: Karudio has ice powers, in contrast to Ponygon's fire.
Harmless Freezing: Surprisingly, a subversion. Karudio's final spell produces such sheer cold that it's even dangerous for himself.
Ashuron & Riin Vise
Ashuron first makes his appearance as one of the final ten demons in the fight, an incredibly powerful dragon. After testing Zatch in battle, he reveals that he is seeking to defeat Clear Note, an evil demon with considerable strength of his own.
Badass: He is one of the "unbeatable" demon children along with Brago, Zeon, and his brother, and he shows it during his fight with Clear.
Magic Mirror / Cool Gate: Two of these were apparently summoned by the Gurādo Ma Kofaru spell in the manga. Cherish uses them for exit portals for the projectiles of the aforementioned spell. Basically allows her to fire from three different locations without moving.
Samus Is a Girl: Ted actually believed that Nicole was a boy when he met her by the first time, due of the clothes she was using.
Yandere: Played for Laughs. And to be fair, she's still not all that bad (ex: she was jealous of Filler Arc girl Shion and considered her a rival for Kiyo...but at the end, when it's announced that Shion has transferred out of the school, she's actually genuinely sad about Shion's departure.)
Smug Snake: He actually is incredibly powerful and can do things such as fly and mentally dominate others without the use of his book. But faced with someone he knows is his equal or superior and he isn't so smug.
Actually not a villain herself, but manipulated by Zofis. Sherry's oldest and most trusted friend.
Affably Evil: Rarely loses her cute, smiling demeanor even when she's being evil.
Break the Cutie: Her backstory. Zofis is able to use this to his advantage. . .
Broken Pedestal: It seems this way at first, when Koko, under Zofis' control, tries to break Sherry's spirit by revealing that she actually hates Sherry and is a truly evil person all on her own. Subverted in that, in the end, this really is all a trick of Zofis', and Koko really is the good friend Sherry remembered her being.
Laser-Guided Amnesia: Zofis removes all memories of her actions while evil. He refuses to do so until Brago tells him that if he doesn't, he will personally make Zofis' life in the demon world a living hell.
In some ways it is. Unlike other people whose minds Zofis simply controlled, Zofis created an entirely different personality out of the dark feelings in Koko's heart so that she would be his bookkeeper. Zofis restores her heart to normal after he gets beaten.
Put on a Bus: Despite her being Sherry's initial reason for fighting, she totally disappears after Zofis is sent back. Justified, in that she goes off to college and Sherry wouldn't want to remind her of the battle anyway.
A four-legged beastlike demon who seeks to resurrect the giant demon Faudo for his own goals.
"Well Done, Son" Guy: We find out in flashback that everything he did was due to the pressure of representing his family in the tournament, and he was seriously conflicted about some of the things he did.
A demon with strong electrical powers who looks uncannily like Zatch. He's tied to the loss of Zatch's memories.
Adaptational Villainy: In the manga, Zeon does start out rather dickish but as the battle goes on we start to see he does have a noble side and that his actions were purely driven by jealously which he eventually overcomes once he sees Zatch's past. In the anime, no such development exists, he's evil through and through and has nothing but contempt for Zatch to the bitter end, even when he's beaten. This was because the author had broken his hand as he was in the midst of the story arc and the anime rapidly caught up before he could do the battle between Zatch and Zeno. So the animation staff just had to go with anything and just ran with what they had.
Freudian Excuse: His grudge against Zatch? He believed that, since Zatch got the incredible power of Bao, and he himself had to go through Training from Hell, that his parents favored Zatch. Once he sees Zatch's memories for himself, he has a moment of Heel Realization and repents.
Kick the Dog: Beating Rops was all part of the competition, but he rubs it in by having Dufort Zeker the already burning book, destroying it instantly so Rops doesn't have the chance to give his bookkeeper a farewell.
Freudian Excuse: Dufort was raised in a lab environment from childhood, treated cruelly and anyone kind to him was removed. After years of torment and testing, he was given one final battery of tests that opened the path to his release, all while taunted by the scientist who had ruled his life. Turns out that A)His Answer Talker was being used for military application, B) He was being released into the Arctic to die rather than being freed, and, oh, C) His mother sold him for ten thousand dollars. Teaming up with Zeon doesn't seem so far-fetched, considering...
Physical God/Invincible Villain: His first appearance; he hands Brago his first and only non-friendly defeat, destroys the full-power Baou Zakeruga, and nobody but Ashuron is able to lay so much as a finger on him (Brago pitched in at one critical moment, but only because Vino was out of energy). Interestingly enough, the fights with his various powered-up forms are much more even thanks to the heroes also getting much stronger.
Gash self proclaimed lover who chase after him for long times. Partner with Uri, a poor man who Patty promised to help take of his hungry family in exchange for helping her find Gash.
Big Eater: All mamodo are this, but Penny loves sweets in particular.
Distaff Counterpart: To Gash. When she cut off her hair she look almost exactly like him. Their spell mirror each other and notibly "So Giaku" and "Baou Zakeruga".
Evil Is Petty: She joins in with Zofis simply because Zatch doesn't remember her in the demon world despite the fact he lost his memory. They did try to explain this to her but Kiyo flubbed the explanation making Penny think she was being taken advantage of.
Power of the Void: His spell theme. Works slightly different from Clear's and looks drastically different.
The Unintelligible: Goomu, albeit Mir (and arguably Kanchome) can understand what he is saying.
Thousand-Year Old Demons
Although not one of the demons Zatch and company fight, Goren is important because his spell is the one that sealed so many demons into stone in the first place. Did not become king, ultimately, as that honor went to Zatch and Zeon's father.
Dangerously Genre Savvy: He might have let Zatch's Zakeruzem hit him the first time (and then Zakurga'd his arm with a painful explosion), but after that, he figures out its effects just as quickly as Kiyo and dodges all attempts made on him. Until Laila and Albert restrict his movement, that is.
The Dragon: Kinda looks like one, and Brago explicitly states his power is greater than Zofis's own.