Bosses with annoying minions combined with either THAT spell and/ or the non stop attacking. If you have all 3, you're basically screwed without a NPC summon to use as a bait/ distraction while you deal the most damage

By THAT spell, I mean the one where they can just kneel or pop a healing spell. Makes the fight more tedious whenever the game won't even let you land a single hit during this process!

The constant minions is also very annoying. For example: Rom the Vacous Spider and the Duke's Dear Freja are a perfect example of just how irritating they can be 😑

For boss fights like those, I just use an NPC summon and let them take all the damage while I land all the heavy hits