Heroish is a drug you can buy from a merchant in the lower-left of the Ravinale Marketplace. It increases your Psy Defense by 30% and Psy Power by 30%, which in turn increases your health and psy points. The effects are only temporary, however; how long they last depends on how much you buy. You can buy a small pouch for 100 gold, or a large pouch for 250 gold. A small pouch lasts for 2 battles, while a large puch lasts 6 battles. You will be informed when the Heroish wears off.