Behold, my notes for the final battle in Miss Demeanor!
The Warmaster is fought in 3 phases, the 1st is just him - who gets stronger when the heroes are not in melee with him. The 2nd invites Lair actions into combat, and the 3rd phase transforms The Warmaster into a monster that soaks anything and everything.
All in all - this fight was a delight. It was the strongest Io Boss so far (and I'm already thinking of more challenging encounters)
Enjoy my madness notes!