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.