[SPOILER] The last boss, and ability cards

[JacobMIX]

So i was fighting the final boss with:
Fire Sword (Sword ignites enemies)
Orange Peril Ring (More DMG on when in peril/low health)
Tincture (Attack up, defense down)
Inverted Ash (Turn HP Potions into MP Potions)
I was learning the boss well, but was struggling. Then there's ANOTHER PHASE?
So i take Fire Sword, switch it with Cyan Peril Ring (Makes it harder to get one shot?)
And switched Inverted Ash for Perfume (Stamina recovery speed increased)
And i do WAY more damage, and beat both phases on my next attempt.
Is this intended? I feel Fire Sword gimbed me during the fight.
I know you can't set the boss on fire with bombs. But i thought it'd still do some damage. It really seems like Orange Peril Ring or Tincture didn't get all their damage because of it. Am i missing something? Does the Fire Sword just disable the other ability cards or does the boss immunity make the dmg not calculate the same?

[Songbird]

Fire sword in general seems to affect direct damage in a pretty negative way. For example, you outright lose the ability to damage certain enemies like skeletons. Not entirely sure on the mechanics, but it's definitely not just adding the fire without changing the base damage behind it.

[JacobMIX]

That explains a lot. I had some enemies i couldn't damage with normal attacks or even Ice Dagger. Thought the game just wanted me to use the shotgun, and Inverted Ash on those. But this makes much more sense. (Granted only only experience it late game with 2 enemies. Both being at a hero's grave statue. The purple enemy that ambushes you in The Quarry, and the left waking statue in the The Great Library) This is good to know tho. Hope it get's fixed. For now i'll just tell my friends not to use it if they start playing the game.

[Warlord]

It almost seems to me as if damage gets capped. After my NG+ run, I seemed to do the same damage no matter how many more times I upgraded my ATK stat. The Tincture seemed to have no effect either.