The Impromptu Villains are a series of people who, either voluntarily or by force, take a dose of Trigger, a Quirk enhancing drug that makes them more powerful, but also weakening their sense of reason. The Trigger they consume is an adulterated version distributed in Naruhata’s streets by the agents of the Villain Factory. The drug has been mixed with uppers in order to boost its user quirk and also make them more aggressive. Under Trigger's influence, the user transforms into a more monstrous version of themselves, and generally begins to cause rampages, destroying street furniture and endangering the lives of innocent people. Usually they are stopped by the Heroes or by the Naruhata Vigilantes.
The reasons why the Villain Factory distributes Trigger between thugs and lower criminals to cause villain outbreaks is to collect data, information and samples from the users and their Quirks. Those who show potential and a powerful Quirk are kidnapped by the criminal organization, and modified by bio-engineering to turned them into Next-Level Villain. However, the main objective of the Villain Factory is still unknown.
Known Impromptu Villains