My Hero Academia's fourth season is building the foundation for the main thrust of the Shie Hassaikai arc, and the latest episode has debuted one of the most important pieces. Overhaul's been planning something in order to bring his yakuza group to the top of the food chain, and it seems part of his plan involves a dangerous quirk boosting drug that was unleashed in the latest episode of the series. There's currently no telling just what it is, but given what it does, it's clear that it's not something that can be ignored.
Episode 68 of the series sees Kirishima begin his official work study under the pro hero Fat Gum, and it's here he comes face to face with the effects of a drug that immediately makes a criminal's quirk a hundred times stronger than it actually is when he injects it into his body.
When a group of criminals is taken down by Fat Gum and Tamaki Amajiki, one in the crowd wants to avenge his compatriots and fires a gun at the two heroes. Kirishima manages to jump in front of Amajiki and saves him in time, but the bullet somehow makes it to where Amajiki can't use his quirk. This leaves Kirishima to chase the shooter on his own, and when he catches up, the shooter panics and pleads.
He mentions how his quirk is useless and just makes it to where he can sprout tiny razor blades from his body, but in order to fight he takes a small red vial out of his pocket and stabs it into his body. He soon writhes around and giant blades emerge from his body. This drug made it to where his quirk is now even more deadly than before, and the fight against him pushes Kirishima to unlock a new level of power.
Seeing that it gave Kirishima this much trouble with a quirk that originally started out as a relatively weak one, there's no telling what this boosting drug will do in the hands of a stronger quirk. There seems to be a time limit to it, but this is factored into Overhaul's plans for the criminal underworld. The threats are about to get a lot more severe.
My Hero Academia was created by Kohei Horikoshi and has been running in Shueisha's Weekly Shonen Jump since July 2014. The story follows Izuku Midoriya, who lives in a world where everyone has powers, even though he was born without them. Dreaming to become a superhero anyway, he's eventually scouted by the world's best hero All Might and enrolls in a school for professional heroes. The series has been licensed by Viz Media for an English language release since 2015. My Hero Academia will also be launching its second big movie, Heroes Rising, in Japan this December.