Biography
dangerous or at least unsettling villain with a childlike nature, which creates a dissonance between innocence and savagery. Such characters can become rich sources of Nightmare Fuel, especially if their childishness is never explained. Contrary to the term, many examples are not necessarily psychopaths in the clinical sense. Misaimed Fandom may not be out of the question, either; sometimes the character's more "Moe" attributes will be picked up on and subjected to Flanderization.
The exact extent of the character's childishness will vary, and in general Psychopathic Manchildren can come in several varieties, with possible overlap. Such a character may:
Be a big Dumb Muscle, often mentally challenged, that operates under someone else's direction. This type may be the most common, and also the most likely to play to the audience's sympathy. Expect them to try to Pet the Dog, often with disastrous results. Could be a subversion of Dumb Is Good.
Seem superficially powerful and cruel, but have very childish or simplistic goals, motivations or world views. Has a tendency to overlap with The Hedonist. Usually extremely unscrupulous, vindictive, irresponsible, and vengeful, and particularly likely to view consequences as a score to settle. It's All About Me is a core character trait: they want what they want when they want it, and if you're in their way, you either get out or suffer the consequences.
Actually possess a lot of power, intelligence, and/or prestige, but also have some childish qualities or behaviors, to fit in with a certain aspect of the story being told, or else advertise that there is something seriously wrong with them, to make them creepier. These are most likely to be a story's Big Bad. These flaws are also often Fatal Flaws, and will be a meaningful factor in why what should have been successful plans fail, or why they walk into something that more sane and/or mature villains would have avoided.
This one is a literal example: Appear cute and harmless on the surface, but actually be this trope. Especially common with female examples, because of the stereotype.
Be subject to a personal variation of Values Dissonance where violent, savage actions are viewed by the character in question in the same light as regular play is viewed by most real children. This variant is often an especially strong source of Nightmare Fuel due to the uncanny dissonance between their childish demeanor and the viciousness of their actions.
Be completely or largely inexplicable, and the discrepancy between the different parts of their personality Played for Laughs.
Have a genuine medical disorder, such as Narcissistic Personality Disorder or (more commonly) Antisocial Personality Disorder.
What makes this character stand out is that he is The Sociopath in that he is mostly incapable of feeling empathy, shame or remorse but unlike other sociopaths, his mental immaturity prevents him from even imitating emotions or indeed even realizing why he takes his desires for granted and fails to even superficially consider why others would disagree or why he isn't entitled to everything. The more charismatic type is excepted from this, of course, though it usually still shows up in some fashion; these types are often impulsive or prone to abandoning plans for stupid reasons, and may have trouble grasping cause and effect. Whichever version these types of characters qualify as, often they are not fully aware of how nasty their actions actually are. In some cases (though not all), a Heel Realization may cause the character to develop into a better person. A more innocent or well-intentioned example may be a Noble Demon. Unlike the more benign Manchild who is presented as virtually Always Male, this can appear in either gender.
One way to use this character is to face him off against a jaded, cynical, or shady Anti-Hero, to play with traditional hero-villain relationships by making the villain more innocent than the hero (at least in theory). (Easier if he's a major villain in his own right.) Another interesting twist is to make this character the Designated Hero and match him with an Affably Evil villain.
Most of the time, this character trope has a Hair-Trigger Temper and is prone to Disproportionate Retribution because of it.
When one of these is running a country or occupying a similar position of authority, you have The Caligula.
The grown-up equivalent of Creepy Child and the near-inversion of Enfante Terrible. Often an enemy of a Sociopathic Hero though the two aren't mutually exclusive (and tend to overlap quite a bit) and contrast with the typically more benign Manchild. See also Cute and Psycho and Ping Pong Naïveté. Related to, but distinct from, Kids Are Cruel and Teens Are Monsters. Can and often does overlap with Immortal Immaturity.