How do I defeat the Mutant Hydrangeas??? They have a seemingly unblockable ability that cripples everyone's attack, and won't die no matter how much firepower I throw at them before they start using that. I tried guarding to wait out that ability, but they don't seem to run out of mana.
Likewise, the Ogre Commander seems to be absurdly tanky as well. I couldn't take him down even when he missed multiple times in a row.
EDIT: I have made it to the Low-Demon, but he is also basically invulnerable unless I can somehow stop him from attacking... well, anyone, really. He one-shots Charlotte (needed for attack buffs) and Paul (the only one who can deal anything approaching decent damage). I did get one attempt where RNG went about as well as it could, and then he split into five.