^ it’s not even lore, it’s like a recurring canon joke, though she’s never actually drugged anyone in a harmful way. there are multiple mini comics that appear in game, an umayuru episode, and there’s an in-game event where you collect points in order to get rewards, one of which includes raising the inheritance stars of your umas (only possible through this event) … and you collect your rewards by “visiting” tachy’s lab, which is also canonically something that she has and is implied holds questionable substances (or at the very least substances capable of questionable chemical reactions)