they need to make dark perpetua easier. I saved before the fight and now I'm softlocked because she keeps two shotting me.
As already implied, she's weak to Aphrodisiacs and the likes. Anyway, what I was going for with my previous message was more: A terrible idea idea to save right before boss fights, more importantly, overwriting your save with that. Always keep a save at the main town plaza, you might lose some progress, but as a silver lining… upon failure/hitting a roadblock, you can always reload and come back better prepared.
You screwed yourself over on your own, that's not an issue of the game.