Complete Monster/Nickelodeon

""You will learn respect, and suffering will be your teacher!" —Fire Lord Ozai in Avatar: The Last Airbender just before permanently scarring his own son." Much like Cartoon Network, some Nickelodeon shows have their own monsters as well.


 * Avatar: The Last Airbender:
 * Fire Lord Ozai, a genocidal, child-abusing fascist dictator who seeks to Take Over the World and has dedicated weeks at a time and large portions of his national army to hunting down and killing a twelve-year-old and his friends. Perhaps best exemplified in the first episode of the four-part finale, where his reaction to news of rebellions in the Earth Kingdom is to try to incinerate the entire continent. While the aforementioned heinous act is his crowning achievement of irredeemable abomination, he's also manipulated his wife into murdering his father to usurp the throne from his grieving older brother Iroh - and then thanked his wife with banishment from the Fire Nation - and physically abused his son Zuko, by burning his face for speaking out of turn, and shooting him with lightning when he decides to join Aang. Furthermore, he also cruelly manipulates his daughter Azula into becoming his perfect little villain, to the point where she completely wrecks her emotional and mental health from the pressure, only to reveal that he doesn't care about her at all, and will discard her as quickly and easily as everyone else. Even after his downfall, he stills tries to manipulate his son Zuko into being a tyrant like himself in the graphic novel miniseries, The Promise, only giving up in rage when he deemed him too weak and beyond hope of being changed. He doesn't regret any of those moments and feels no remorse for the consequences.
 * The graphic novel miniseries, The Search, makes him even worse, if that was possible. It's revealed he never had any true lover for his wife Ursa, seeing her as a possession to covet rather than a romantic partner. The reason why he treats Zuko so horribly?
 * The tie-in novel, The Rise of Kyoshi, gives us Xu Ping An, a ruthless Firebender warlord. With a finely-honed, superficial sense of charisma, he uses to reign in a loyal gathering of marauders with which he pledges to overthrow the law and let anarchy reign. Xu put entire villages of "abiders" to the sword, leaving countless corpses stacked behind him until his rampage was finally stopped by Jianzhu. When inadvertently broken out eight years later by the Avatar, Kyoshi, Xu muses that the land has forgotten his name and pledges to scar his name into history in a way they will never forget. To begin his new wave of bloodshed, Xu captures a family and forces them to watch as he dunks the father in and out of a pot of boiling water, gleefully intending to move on to slaughter the nearest town. Xu even uses his rare ability to bend lightning to savagely torture Kyoshi, proclaiming himself absolute and that all anyone can ever hope to do against him is obey.
 * The sequel series to the above, The Legend of Korra gives us two similar characters:
 * Yakone is a particularly nasty bloodbender from the Water Tribe who factors heavily into the story of Book One as it's Bigger Bad. The backstory shows him as a feared crime boss of Republic City in it's early days, one who used illegal bloodbending to control and harm others. His bending was so strong, he could bloodbend without need of the full moon and planned to use this power to Take Over the City until Avatar Aang had him brought to justice. But he simply bloodbended the entire coutroom in order to make his escape, and when Aang tried to stop him, he bloodbended his body with the intent of snapping his neck. Fortunately, Aang overcame him and took his bending away. A few days later, Yakone's gang broke him out of prison and gave him plastic surgery so he could escape the city and go start a new life elsewhere. Back home in the Water Tribe, he met and wed a woman, having two sons by her: Noatak and Tarrlok. When the boys were discovered to be gifted waterbenders, Yakone's greedy, power-lusting and vengeful old self reawakened in him and he took his sons out in the wilderness to give them secret training for developing special bloodbending like he used to have. Not only did he psychologically, emotionally, and physically abuse his kids, pushing them in their training and putting the younger son Tarrlok down as a weakling for not having the stomach for bloodbending, but he flat out told them that using their gifts to help him take his revenge on the Avatar and Republic City was the reason they exist: that they were born and live to be his tools for vengeance! He finally crosses the line when he orders the brothers to bloodbend each other. Of course Tarrlok refused, and Yakone was about to savagely beat him before Noatak bloodbended him instead to protect his brother. (Even here, Yakone roars "I made you! YOU'RE MINE!") Noatak ran away and Yakone was unable to find him, sending him into a Villainous BSOD because his hopes of revenge were dashed. He died shortly afterwards, having lost the will to live. The worst part of all this?
 * Unalaq, the Holier Than Thou chief of the Northern Water Tribe, is Korra's Evil Uncle who serves as the Big Bad of Book 2. Beneath his self-righteous spiritual preaching, Unalaq craved nothing but power, and would do anything, no mater how deplorable, to get it. He is a Hypocrite of the worst kind, shown clearly when he arranged for a habitat for spirits to be desecrated all to set his brother Tonraq up for a fall. He had more resentment towards his older brother than Ozai did for his, having been responsible for getting said brother banished from the Northern Water Tribe all so that he could take the mantle of chief that was his brother's birthright, and more disregard for his two children than Ozai did for his too: he treats them as disciples to carry out his wishes and when his son Desna is nearly fatally injured in an attempt to open a Spirit Portal, he expresses no concern and advocates leaving him to die in favor of focusing on getting the portal open. Unalaq later forces Korra's cooperation in opening the portal by attacking and threatening to destroy the soul of Jinora, a young girl. When Korra caves in, he nearly kills her anyway and tries to destroy Korra's own soul. Unalaq later assaults the Southern Water tribe and delivers a decisive and near fatal beating to his brother Tonraq, sparing his life solely so Tonraq can see him win completely. And in Book 3, it's revealed that he's the reason why Korra grew up in an isolated security compound for most of her life.
 * Dark Danny/Dan Phantom, from Danny Phantom, who was born of a fusion between the ghost halves of Danny and his nemesis, Vlad Masters. He is the only villain in the show who has actually been implied to kill anyone, which is saying a lot for a Nickelodeon show. His origin is pure Nightmare Fuel - the first thing Dark Danny does upon his conception is brutally murder his human half, before embarking on a campaign of random destruction for his own amusement. In the future, Dan has conquered the world, singlehandedly handicapped multiple ghosts, and ruined what is implied to be a very large portion of the Earth, turning it into an apocalyptic wasteland. Realizing that other parties have been meddling in the time stream, Dan decides to personally ensure his rebirth by making sure the catalyst that caused his transformation happens. Since he was created following the deaths of everyone he loved, he attempts to murder his parents, his sister, and his two best friends. Dark Danny stood out as being one of the darkest and most chilling villains in the series, even turning series Big Bad Vlad Masters into The Atoner for his role in Dark Danny's creation. The guy is so bad, that this is the only time that the Master of Time has had to interfere to keep it from happening.
 * The Adventures of Jimmy Neutron: Boy Genius has several silly villains, but one who really stands out as completely vile is Meldar Prime, who ran an intergalactic game show where he forces different alien races to compete against each other and he blows up the losers' home planet. The losers, being the only survivors of their kind now, are enslaved by Meldar, who also makes a profit off of their planets' destruction and the ratings it brings, which allows his twisted show to get more success and continue. When the humans and their opponents, the Gorlocks, refused to play by his rules and joined together to stand against him, Meldar tried to have them all killed. He even made particularly vicious attempts on their lives himself using power granted to him by time-space bending energy generators. Not even Tim Allen's funny delivery in voicing the character could change the fact of how evil he was and that Jimmy and the others treated him as a very serious threat to the entire galaxy.
 * Justin Hammer from Iron Man: Armored Adventures is a young weapons manufacturer whose company Hammer Multinational is the main competitor to Stark International. Hammer hires the super villain known as Mr. Fix to work for him and later injects Fix with a nano virus that will kill him if he disobeys Hammer. After Iron Man defeats Hammer's Titanium Man armor, Hammer blames Fix for the armor's failure and uses the nano virus to kill Fix's body, but uploads his mind into Hammer's computer systems, much to Fix's dismay. After Stark International lands a big military contract, Hammer decides to get revenge by placing a control device on Stane's Iron Monger armor and sends Iron Monger on a rampage. After receiving blackmail messages from an unknown party (actually sent by Mr. Fix.), Hammer becomes increasing paranoid and Ax Crazy. Hammer starts attacking anyone who he thinks may be responsible, including his own men. Hammer uses a new chemical weapon called Z Gas to turn crime boss Count Nefaria into a zombie and then kidnaps and tortures Killer Shrike, one of his former henchmen. Hammer then turns Shrike into a zombie. After Iron Man broadcasts evidence of Hammer's crimes across the globe, Hammer starts to lose it and plans to release the Z Gas on New York City.
 * The Wizards of the Black Circle in Season 4 of Winx Club are real pieces of work. They commit atrocity after atrocity in their quest to corner the market on Earth's magic by sealing away all of Earth's faeries. Their first meeting with the last Earth faerie Roxy, a nineteen year old girl who has no idea she's a faerie and thus is no real threat to them, is also really, really creepy. In one episode they turn the adorable magical pets the Winx have been putting up for adoption into horrible monsters as a distraction. After pulling an I Surrender, Suckers gambit, they laugh with glee at the prospect of trapping the Earth faeries in a hellish abyss. Finally, unlike the Trix, they actually succeed in killing off one of the heroes, namely Nabu. Their leader Ogron even steals the Deus Ex Machina that could have saved him and wastes it on a flower, again with an Evil Laugh. These guys are the biggest reason Season 4 is considered Darker and Edgier than the rest of the series.
 * Kung Fu Panda: Legends of Awesomeness has these two:
 * Tong Fo. While nearly all the villains of the franchise have at least one sympathetic or redeeming trait, the character most likely to be called a Complete Monster is Tong Fo, being Faux Affably Evil and seriously cruel and deranged. He makes his debut trying to destroy the Valley of Peace with a powerful hammer, seemingly for no reason other than because he can, as he never gives any reason for wanting to destroy the Valley. In "Father Crimes" when he manages to capture Shifu, he heavily implies that he's going to torture him, physically and mentally. In "Kung Fu Club", he blackmails Peng into fighting Po to the death by threatening to order Peng's girlfriend to be killed if he doesn't cooperate. On top are his repeated attempts to kill Po in nasty ways, in particular in "Mind Over Manners", where he pretends to want to help Po, then almost immediately reveals that the "help" in question will kill Po by making his head explode. And his reasoning for his life of crime is that he wants to live up to the legacy of his felon grandfather - by going even further than he ever could! His Christopher Walken impression voice can't even disguise what a total psychopath he is.
 * Ke-Pa, from "Enter the Dragon", is an ancient demon who terrorized the Valley of Peace with his army of demons, driving out or killing the citizens. After his army was sealed away by Oogway, Ke-Pa spent decades waiting for the peach tree that his powers are bound by dies, then, with his power returned, transformed into a dragon and lay siege to the Valley of Peace, threatening to eat the citizens one by one. Capturing and torturing Shifu under the belief that he has the Hero's Chi, Ke-Pa tries to crush the Hero's Chi out of him to free his demon army, before doing the same to Po and succeeding. Once his demons are unleashed, Ke-Pa orders them to kill everything in the Valley of Peace, bragging that he will destroy all mortals on the planet and reign supreme.
 * Teenage Mutant Ninja Turtles (2012 series)
 * Victor Falco is the Rat King in this series. The Turtles meet him while investigating a scientist's mysterious disappearance, and while Falco at first seems like a decent guy, it's soon revealed that he kidnapped his colleague in order to mercilessly perform torturous experiments on him that mutate him into an ape-like creature so that he can use the mutated DNA to create a serum to gives himself Psychic Powers. While moderately successful at this, Falco ends up losing his job and having to continue his experiments on rats in private. A freak accident leaves him blind and disfigured, but also grants him the psychic ability to control rats. Claiming to be in touch with the rats' views, Falco turns against humanity for being "filthy vermin", adopts the name Rat King, and seeks to have his rats take over the city by driving the humans away. He also ruthlessly Mind Rapes Splinter several times to break his spirit and turn him into his slave. He goes as far as to manipulate Splinter with memories of his dead wife and daughter, and then uses him as a weapon to destroy his own sons! He later returns again, kidnaps several civilians, including teenagers, and plans to experiment on them to turn them into hybrid "rat people". While his first attempt results in a deformed creature that is immobile and in constant pain, it does nothing to deter him from his experiments. He unleashes a hoard of rat monsters onto the city to attack and kill several innocents, taking psychotic glee in it the whole while. And then he assaults Splinter's mind to get him to destroy his sons again. And despite his supposed kinship with his rats, he has no problem using them as test subjects and disposable sacrifices. When all is said and done, not even the Shredder is as vile and malevolent as the Rat King in this series.
 * The primary villain of the first three seasons of the series, Kraang Prime, is a grotesquely large, demented Utrom warlord who fancies himself a god. Developing psychic powers from mutagen, he brainwashed millions of innocent Utroms, crafting an army of servile "Kraang" to invade and destroy planets, ultimately setting his sights on Earth as his petri dish. Spending millennia killing and torturing humans to create a new Dimension X, he then decides to turn the massive metropolis of New York into a mutant colony, succeeding and transporting millions of victims to Dimension X as slaves. After that, his scope expanded to the entire planet, with him loading a missile with mutagen as a last resort. Relentless, cruel, and deceitful, Kraang Prime was a massive threat to the Turtles and all Mutantkind.
 * Kavaxas in the same series is the draconic ruler of the Netherworld who desires to bring about the apocalypse. After he's summoned by Tiger Claw, Kavaxas is forced to work alongside him and the Foot clan so they can resurrect the Shredder and defeat the Turtles and their friends. After Kavaxas brings Rahzar back to life as one of his minions, he goes after Hattori Tatsu and kills him before stealing Shredder's helmet. He later attacks Don Vizioso's gang and kills some of his mobsters before stealing the Shredder's heart, all while repeatedly trying to kill the Turtles. With both items in his possession, Kavaxas successfully resurrects the Shredder before betraying Tiger Claw and the Foot clan; Kavaxas proceeds to unleash thousands of spirits onto New York City as he attempts to cause The End of the World as We Know It.
 * Voltron Force:
 * Dr. Maahox, King Lotor's second-in-command is a cyborg occultist and Mad Scientist who was exiled from his home planet of Calum for Playing with Syringes. After he and his partner Kala resurrect Lotor using Haggarium, Maahox betrays Kala by transforming her into a Robeast. While Maahox ostensibly serves Lotor, he is the one pulling the strings in their partnership and is the brains behind operations like draining the minds of the Baltons, nearly eradicating all life on Arus, and attempting to ignite a massive amount of volatile Haggarium just to see what would happen. When Sven gives him the Blue Lion in exchange for a cure for his and his infant son's Haggarium poisoning, Maahox reveals that there is no cure and that he intends to raise Sven's son as a test subject and Tyke Bomb. Eventually growing weary of Lotor, Maahox murders him and turns his castle into a massive Robeast whose power he tests by having it blow up Planet Doom. Declaring his intent to spread chaos and death throughout the universe simply for the sake of it, Maahox begins his rampage on Earth, leveling an entire city just to draw out the Voltron Force.
 * Sky Marshal Herbert Wade wanted nothing more than to be a member of the Voltron Force, but when the Lions rejected him due to sensing evil in his heart, Wade snapped and developed a pathological hatred of Voltron. After the Voltron Force toppled the Drule Empire, Wade forced the Lions to go berserk during a victory celebration, which turned everyone against them and caused them to be sealed away on the planet Arus. When the Voltron Force reassembles to combat the resurrected King Lotor, Wade usurps control of the Galaxy Alliance; while Wade publicly claims to have the Galaxy Alliance's best interests at heart, he privately confesses that he really only cares about money, power, and eliminating Voltron. Anyone who opposes Wade is condemned to the Void, a gulag whose inmates are routinely jettisoned into space for Wade's amusement. Along with enslaving, plundering, and razing worlds, Wade at one point hijacks Voltron, using it to try and destroy one of Earth's metropolises while ranting that its citizens all deserve to die for their veneration of Voltron. After being arrested, Wade is sprung from custody by the Kala Robeast, with which he willingly merges to create a monstrosity that poisons Daniel with Haggarium before nearly assimilating Voltron.