@Raine
Very nice theory Raine! I think it can be polished a little bit. I’ve edited your idea a little bit.
The party goes find a boss either a demon type or mutant type boss. This is because the Cleric can use Paladin`s turn undead skill for a chance to kill either a Demon or Mutant type monster. I did a tally and so far there are 101 unique bosses [bosses with the same name but different colour/title were essentially taken to be the same]. Out of these 101, 19 of them are mutant type, while 32 are demon type. This means that 50% of all bosses have a chance to be killed with turn undead instantly. Since we can change the drop anyway, it’s better to aim for these types. The Oracle uses Clairvoyance to see if the boss will drop what they want, if not use Resetting. While fighting, the Oracle can use Forecast which seems very useful to deal with boss. When the boss is about to die, first make your Mage cast Enlarge Body( Thaumaturge’s skill), this will double the remaining HP but will also double exp and drop rate, then bring HP back to it’s original and let Doppelsöldner finish it with their Double Pay Earn activated to earn x2 reward (that is if the reward includes dropped item). Then Chronomancer cheats time with their freaking Back Masking so they can revive the boss/party to a previous time. If you have a second chronomancer they can cast Black Mask after waiting just 10 sec. To decrease the 300 sec cooldown of Black Mask make your Cleric use Dievdirby’s Laima statue before casting Black Mask. Also I wonder about Oracle’s change, which changes the enemy based on a random level range. But i’m sure there is a mechanism to prevent bosses changing to ordinary mobs or vice versa. So even if you come across a non-demon/mutant boss you may be able to change it to a demon/mutant boss (50% chance).
Also there is still one issue with Black Mask. So basically it if the boss goes out of the bubble, the boss disappears from existence. (or maybe you are trapped in the distortion of space till it ends). Same thing if you’ve just resurrected your friend back to life. I still need some one to confirm how Black Mask works.