I feel like I've hit a soft lock. I'm at the point where Weiss takes a hostage, and I cannot beat the fight against him. He has an insane amount of health that my attacks do very little to reduce, while a single one of his attacks takes away about a third of my health. He's also got this "blue attack," which I assume is meant to be his Ultimate, but why the hell is he allowed to just spam it? When I use my Ultimate, I have to wait for the gauge to refill before I can use it again. I don't have enough money to buy a lot of healing items, and the game won't let me leave East Street to go grind. I would lower the difficulty, but the game says that certain achievements can't be unlocked on Light, so I don't really want to do that. It seems like my only chance at beating the fight is to just keep countering and hope I don't fuck up the timing too many times.
Edit: Did they even playtest this fight at all? Did they just expect you to grind up an extra 50 levels or something? If that was the case, they maybe should have given a warning or something, instead of just throwing you into it and then not letting you leave. This may actually be the worst boss fight I have even seen in any video game. I was really enjoying this game, but this one fight is going to make me drop it and never play again.