Psychopathic Manchildren in fanfiction.
- In the Day of the Barney Trilogy, Thorton Marshall is this. Adolf Hitler is also implied to be one, given that he was the only person who Barney corrupted that was not a child.
Crossover
- The Butcher Bird (One Piece & Tokyo Ghoul): C fits this trope to a T - a ghoul clone with very little morality due to being raised by pirates and his own dietary needs.
- Code Prime: Charles quickly reveals himself to be one: Megatron spells out to him that his dream of a "world without lies" is some childish fantasy that he indulges in because he is too infantile to actually change the world through his own will.
- Abraxas (Hrodvitnon): San has a rather Manchild personality and at times he's like an inquisitive puppy. The Psychopathic part, though it becomes downplayed due to San's Heel–Face Turn Character Development, still shows itself at times; in how San is generally more nonchalant about violence than his sister Vivienne is, and his Blood Knight. San-Who-Could-Have-Been/Youngest Brother plays this trope straight, being essentially a clone of San who lacks his counterpart's Character Development.
- A Thing of Vikings: Sir Henry throws a tantrum when Hiccup and Astrid refuse to let themselves be captured.Sir Henry: No! No! This is all wrong! I caught you! Don't you have any honor?! Stay caught! You're my prisoner! I claim your ransom!
- Vanitas from The Shrouded Path just wants to be loved by his surrogate parents. He's willing to go to extreme measures to obtain this.
- How Bad Can A Little Gossip Be: Mr Ricci acts more like a playground bully than a grown man.
- In the My Little Pony: Friendship Is Magic fanfic Cupcakes (Sergeant Sprinkles), Pinkie Pienote is a Psychopathic MareFilly who loves inviting her friends to 'parties' which start with silly jokes and end with their hideous and torturous deaths.
- Prince Jewelius from Loved and Lost is a highly skilled Manipulative Bastard and Chessmaster who does a great job at appearing reasonable and nice in the first few chapters and successfully usurps Equestria's throne while tricking the public into rejecting his aunt Princess Celestia, Shining Armor and the friends of Twilight Sparkle as traitors and manipulating Twilight herself to stop trusting all of them. However, it becomes clear over time that he's basically little more than an overgrown and capricious colt who hates his more well-known aunt Celestia and cousin Princess Cadance (who regards him as her younger brother) simply because he "stands in their shadows", so he attempts to destroy their reputations and kill them, wanting his own legacy to surpass theirs. He not only sentences Twilight's friends to slavery, but he makes the life in their hometown miserable through raised taxes and trading prohibitions. Why? Because he felt greatly insulted when Rarity praised Cadance's wedding in his presence!
- In the Pony POV Series, the Dark World version of Fluttercruel more than qualifies. Despite being over a thousand years old by this point, she's still mentally a foal who, as Rarity puts it, no one ever explained the difference between a hug and a handgun to — she's a sociopath who gets her thrills torturing and killing things, and throws tantrums when Discord won't let her. This is the result of being raised by Discord, which resulted in her belief that she was showing love to her father by torturing ponies and that she was showing her mother love by torturing her. And this is all before she goes off the deep end.
- Junior Officers: Humphrey, Deborah's abusive father, has some childish tendencies, such as mockingly mimicking his daughters' words and sulking when he doesn't get his way.
- At The Food Court: After having a dissociative episode in which he thought he was a Pikachu, Ash was eventually brought out of it through heavy-duty psychic therapy. Unfortunately, his original personality was broken beyond repair, and he lost his ability to function on his own and regressed to the maturity of a five-year-old, specifically, a barely disciplined five-year-old. Ash is now 27 and throws temper tantrums and screaming fits when he doesn't get his way. He isn't quite as psychopathic as most examples, though, since he still loves Pokemon battling (though he can no longer be a Trainer) and is happy when Tracy and Rhys have a mock battle with him using plush toys. Ultimately, he is like this entirely because of his brain damage and still acts the same as before in his own delusions.
- Rosario Vampire: Brightest Darkness:
- The original Jovian and Jacqueline Kikion who served Hokuto are a mix of Types C and D. They're both incredibly powerful and nearly unstoppable Hot Witches... and they're also completely Ax-Crazy Psycho Lesbians whose idea of fun involves such things as Cold-Blooded Torture, rape, and committing acts of wanton mass murder and city-wide destruction as a matter of course; they even explicitly describe their fights with Tsukune's group, during which they deliberately go above and beyond to kill as many innocent people and cause as much widespread destruction as possible, as "playing." To drive the point home, in Act III chapter 42, Jovian even cheers "Yay, I love killing!" in what the narration explicitly describes as a playful tone, and in Act IV chapter 25, when Gin saves Mrs. Aono's life after Jacqueline blows up Tsukune's house just to torment Tsukune, Jacqueline whines that Mrs. Aono should have died in the explosion and that Gin "didn't play fair."
- Falla Cii, before she was killed and replaced with a Good Counterpart from an Alternate Timeline. Her reaction upon discovering that her parents had chosen her sister Luna to succeed them as rulers of the chronofly kingdom was to throw a childish fit and whine about how she deserves to rule more than Luna, before ultimately picking a fight with Luna and destroying said kingdom, along with the chronofly species except for herself and Luna, in a fit of rage.
- Falla's Good Counterpart also falls into this for a good part of Act IV. As she was Tsukune's girlfriend in her original timeline, she simply cannot accept that this world's Tsukune is dating Moka, to the extent that she throws a temper tantrum and screams that it isn't fair and goes so far as to rig the entire girl's dorm with Death Traps in an attempt to kill Moka. The final trap she sets is quite infantile; a Box-and-Stick Trap containing a blood pouch and a sign reading "Free Blood," which Falla genuinely expected Moka to fall for.
- Kahlua Shuzen retains this trait even after her Heel–Face Turn. Despite being the second oldest of the Shuzen sisters, she often acts like a young child, doing such things like whining and watching cartoons. It's also explicitly noted by other characters that every time Kahlua cries, she throws a temper tantrum; one such tantrum in Act IV chapter 2 almost leads to Yukari getting chopped up by her Blade Below the Shoulder.
- As in the original manga, Gyokuro Shuzen's entire Evil Plan is essentially just her throwing a temper tantrum over the fact that Issa had been more loving and attentive to Akasha than her.
- The Makings of Team CRME:
- The series gives this interpretation to Cinder Fall. She is still the same cunning, skilled, manipulative sociopath that she is in the show, but this series puts some reasoning behind her actions. Her backstory in My Name Is Cinder shows that she was horribly abused by her mother and began to resent the world because it happened. When Salem found her, she was fifteen and wanted to be powerful after killing her mother. Her egomania is a result of her childish desire to be seen as powerful and get back at the word just because one person hurt her. And since she is shown to be The Bully on the show, her sadism can also be traced to this. In CRME, it shows that her attitude and ego haven’t changed much from when Salem started her training. She is still emotionally stunted and refuses to move on from the pain she was caused by her mother. Her violent attack on Melanie Black was because she reminded her of her mother. This starts becoming more obvious as the story goes on. She occasionally throws tantrums and retaliates against criticism in a rather petty manner. Once by physically assaulting Mercury when he joked about a failed persuasion attempt. Another by bickering with her ally about a disagreement."You are not some sort of goddess of death. You are nothing more than an egotistical brat with delusions of grandeur because you're still angry that your mommy hurt you in the past." — Dr. Watts in CRME
- Roman Torchwick starts showing shades of this trope in Roman's Empire. His dream of becoming a top-level mob boss seems to come off as immature when he reveals that he married a woman just to have a queen for his empire. Overall, while he conducts himself in a professional manner, his attitude is more like that of a child at play with the city of Vale as his sandbox. He certainly fills the psychopathic part since he tends to use Neo to settle disputes often. This tactic is basically him bullying others to get what he wants. His appearance in CRME shows him childishly taunting the police commissioner when he's in jail and after he gets bailed out. And he petulantly disagrees with Cinder's decisions to make him work with the White Fang due to his Faunus prejudice. Mercury lampshades this when Roman argues with and taunts Adam.
- Mercury Black's mother, Melanie, from The Black Hearts is shown to have some childish traits in addition to being The Sociopath. She yells at Mercury for some minor reasons, such as him noting that she shouldn’t put up with the abuse from Marcus. One time, she shouts, "You are not the boss of me!" and the way she says it while shouting and cursing at him doesn't suggest that she is very mentally mature. One thing that solidifies the "psychopathic" part is one time she pulls a gun on Marcus when he is preparing to torture a woman. Not to save the girl. She was mad that he wouldn't come upstairs to eat the food she cooked. She even threatens to kill the girl to get what she wants out of her husband.
- The series gives this interpretation to Cinder Fall. She is still the same cunning, skilled, manipulative sociopath that she is in the show, but this series puts some reasoning behind her actions. Her backstory in My Name Is Cinder shows that she was horribly abused by her mother and began to resent the world because it happened. When Salem found her, she was fifteen and wanted to be powerful after killing her mother. Her egomania is a result of her childish desire to be seen as powerful and get back at the word just because one person hurt her. And since she is shown to be The Bully on the show, her sadism can also be traced to this. In CRME, it shows that her attitude and ego haven’t changed much from when Salem started her training. She is still emotionally stunted and refuses to move on from the pain she was caused by her mother. Her violent attack on Melanie Black was because she reminded her of her mother. This starts becoming more obvious as the story goes on. She occasionally throws tantrums and retaliates against criticism in a rather petty manner. Once by physically assaulting Mercury when he joked about a failed persuasion attempt. Another by bickering with her ally about a disagreement.
- For the Big Bad in the Ruby and Nora universe, Salem has some very childish behaviors. She spends time taunting Ozpin just before enacting her plan, not suggesting a lot of maturity on her part. Her address to Remnant discrediting Oz and his allies has some rather childish undertones with the name-calling used (specifically calling Glynda a whore-addicted harlot) and the final sentence calling them "stupid, selfish, incompetent, and most importantly, weak." Even as she fights Pyrrha, she engages in petty name-calling and insults. When angered by Pyrrha's insults, one time she only responds with "Screw you!" Her Villainous Breakdown is essentially just a massive tantrum. And she's absolutely giddy when she is about to get the Relic of Knowledge. Justified since she was locked away in a tower for most of her developmental years. She didn't have the chance to adequately mature mentally, explaining her childish motives and behaviors.
- In RWBY: Scars, the mute Neo monologues in a childish tone, despite at least being in her late teens. She's also brutally violent when she wants to be and is unafraid to kill.
- Sonic X: Dark Chaos features Beelzebub, the Lord of Flies. A death metal druggie and Mad Scientist, he's also a sadistic pedophile who gets off on Cold-Blooded Torture. After capturing them, he ends up raping Chris and almost-raping Cosmo simply because he wanted to feel how "tight" they were.
- Tsali is basically this trope personified, often going straight into Ax-Crazy with his playful attitude towards violence and bloodshed. It's justified later on with the reveal that he was turned into a robot by Cosmo's race when he was only ten, which prevented him from ageing physically or mentally - and the entire Metarex War was basically a genocidal temper-tantrum over it. Also lightly deconstructed, as his lack of self-control nearly ruins Maledict's plans several times.
Unsorted
- Agent Diamond from Akatsuki Kitten: Phoenix Corporation Overhaul. She is stated to be quite intelligent despite less than normal comments, and has proven herself to be extremely powerful. She small, pretty, and has a relatively unassuming appearance and demeanor, which leads her instances of extreme violence, complete with creepy laughter to be even more disarming. And said laughter, as well as her background, show that her values aren't exactly the same as most peoples, particularly as she works directly for the author.
- The Bound Destinies Trilogy:
- Veress, the Big Bad of Blood and Spirit. The reason for her Face–Heel Turn is incredibly petty and childish: she was passed over as leader of the Sheikah in favor of Sheik. In a nutshell, for all of her charisma and power, in the end Veress is nothing but an immature brat throwing a temper tantrum because she didn't get what she wanted.
- Veress' descendant Veran of Wisdom and Courage displays a lot of childlike evil. She has an ego that's bigger than Hyrule and Termina combined, treats killing innocent people and destroying villages as a game, constantly feels the need to gloat to Link and Zelda about how much better she thinks she is than them, and more or less acts like a child with a new toy when she gets the Triforce.
- Female version in Hivefled's Condesce, who along with her partner the Grand Highblood has murdered two and a half thousand teenagers for kicks and horrifically tortured her own son while cooing and cuddling him like he's a puppy.
- "Sweetpea" in Except It Abide in the Vine is this trope portrayed sympathetically. He's an alternate version of the Winter Soldier from a dystopian HYDRA-ruled reality, and he's dealing with the aftereffects of HYDRA brain surgery as well as the usual brainwashing, so he has issues even by Winter Soldier standards. At first, Sweetpea appears to be a vicious, feral Dumb Muscle. Then he gets a chance to calm down, and out of combat he turns out to be a strangely cute, overly affectionate weirdo with some communication problems. Then the team's dimension-hopping lands them in a warzone and Sweetpea bites a Nazi mook's throat out. His overall characterization averages out at "a bit unstable but weirdly adorable outside of combat, pants-wettingly brutal in a fight," a bit like a giant muscular cyborg River Tam.
- In Sonic the Hedgehog fanfic Prison Island Break, beneath his mask of a cruel psychopath, Shadow is this. He has almost zero self-control and is almost pitiable in his subconscious desire for somebody who can keep him under control.
- Psycho in With Pearl and Ruby Glowing, a la his original form in the movie.
