Trigger

Trigger (トリガー, Torigā), also called Boost, is a drug that pushes a Quirk past its natural ceiling while eroding the user's judgment in the same motion. Criminal organizations distribute and consume it, and many countries have made it illegal on that basis. A lawful variant does exist, sold against baldness and erectile dysfunction, though moving it without a pharmaceutical license remains a crime.

It arrives in pre-filled syringes, usually injected through the neck. Production happens in different corners of the world and quality follows the source: batches made in Asia tend to be poor and burn out within minutes, while American product can hold for an hour or two.

In its base form the drug does one thing, amplifying whatever Quirk its user already has. Blend in the right uppers and the result is Ideo Trigger, stronger and far more dangerous. It empowers the Quirk the same way, but it also drives the user into an uncontrollable rampage and rewrites the body into something remarkable. Habitual users pay for it with blackened tongues, a symptom that traces back to the damage the drug does to blood flow.

Injection is the usual route for the Ideo variant, but a version that only needs swallowing has been developed. It works less effectively, though it drops the psychotropic element entirely, so it strengthens without stripping reason or sending anyone berserk. A gaseous preparation exists as well, chemically tuned so that every Quirk user who breathes it loses hold of their power to a degree dangerous both to themselves and to everything around them.

The drug started life as a way to lift feeble Quirks into something formidable. Crime found the use for it almost immediately, bans followed in Japan and elsewhere, and it settled into its permanent role as contraband for dealers and gangsters worldwide. In Vigilantes, All For One takes a particular interest through the outfit the Police Force calls the Villain Factory, helping engineer the Ideo variant that turns its consumers into Instant Villains. He first works it quietly behind the Underground Masquerade, tempting fighters with concentrated doses to sharpen their bouts, then gassing the venue so their Quirks spilled out of control and he could take whichever ones interested him. Years later the Factory returns, putting agents on the streets of Naruhata to hand the drug to junkies and thugs. The chaos is the point: it yields data and blood samples, and the most interesting subjects are abducted and rebuilt as Next-Level Villains, their bodies permanently altered to withstand enormous doses.

In the main series the Shie Hassaikai traffic it to other criminal organizations to bankroll their own experiments. Months after a factory producing it is destroyed and its stock vanishes, three smugglers try to move the drug by sea to their client Flect Turn, run into the Oki Mariner Crew, and one of them doses himself to thicken a smokescreen and disappear into the Verize islands. Searching an archipelago being what it is, Selkie brings in Ryukyu and her team, and together they run the smugglers down and seize the shipment. The buyer turns out to be the international cult Humarise, which already holds enough Ideo Trigger for its plan. Scientists forced into service build them Trigger Bombs loaded with the gas, meant to be released over major cities worldwide so that the Quirk population overloads and dies, thereby averting the Quirk Singularity and, in their reckoning, saving humanity. Pro Heroes deploy across the globe, and a deactivation key built by the scientist Eddie Soul lets Izuku Midoriya, working alongside Eddie's son Rody Soul, shut the master Bomb down while the Heroes clear the rest.

In the main series, an unnamed street villain sprouts, retracts, and masses long blades honed sharply enough that they nick the Hardening of Eijiro Kirishima. The Shie Hassaikai's Joi Irinaka stretches Mimicry far past its usual refrigerator-sized limit to merge with and steer an entire underground facility ahead of the Heroes' raid. Rikiya Katsukame turns Energy Suck into something contactless, draining stamina by simply breathing in. A smuggler boosts a Smoke Quirk to cover his gang's escape while another is stopped by Selkie before the needle lands. Ending expands Whiteline to command every lane line painted on a road. The Serpenters push their Sword Kill Quirks into monstrous faces and full-body blades, Leviathan fights blind and without a sense of self on an amplified Helical Scythe, and a full city's Quirk users overload and die from the gas.

Vigilantes supplies the rest. Rapt Tokage's Lizard reshapes him into a pteranodon, Moyuru Tochi goes from a small flame where his hair should be to a burning rock golem, Soga Kugisaki turns porcupine-like with heavier spikes across his body, and Playtime makes Mario Kugutsu a massive four-armed giant. Akira Iwako grows larger and stronger on a Hardening transformation. Teruo Unagisawa's Eel swells him into a big eel-like thing whose human limbs stay small, mobile enough to bounce off buildings and keep pace with Pop☆Step's Leap; Kuin later doses him repeatedly and rewrites the Quirk into Electric Eel, leaving him a slippery-skinned bulk whose limbs stay muscular but human and who blacks out whenever he discharges. Kuin Hachisuka begins as a distributor rather than a user, turning Queen Bee into a specialized delivery mechanism that infects dozens of Quirk-using citizens and field-tests the drug's potency, then takes it herself for strength and an electric Quirk at the cost of her grip on Tamao Oguro, whose personality partly resurfaces. Dealers Ichiro and Jiro Hotta become humanoid grasshoppers. Civilians caught by it grow blades on fingers and shoulders, swell with muscle, fire electricity from their eyes, leak black fluid from their palms, catch fire, or balloon into dark round shapes with lighter markings that stream water. At the Underground Masquerade the fighters lose control once the gas reaches them, and Bee☆Pop's infection drives every bee inside her to scatter.