Final Boss Battles: Julietta Nolan Part 2 (Hard)
This is the worst boss fight (leaving aside the Pain Area boss of course) in the entire game, you WILL need a plan to pull it off, either a full party of invulnerability buff spam, or pray for the RNG to have the game give you a good bug field setup with Mai's Paradigm Shift, just like in the 1st form, Julietta will put a counterstrike buff (this time for magic attacks instead of physical... that also counterstrikes glitch moves as well) when you get to the 2nd phase and again, either Lucil or Rottie can nullify it swiftly.
This time for my plan to work swiftly I had to replace Liliana with Al, that way in case I needed to recover SP (just in case), I just could use Al's glitch move for the job and keep the items for a big emergency (that never happened during the entire time I played the game anyway), plus I needed a good RNG to have Mai's Paradigm Shift put the bug fields I needed (major corruption bug field is the optimal one to keep Mai using Deus over and over while keeping the other 2 characters safe, and also to carefully perform the other 2 gals glitch move if needed), keeping buffs active whenever it was possible and also not risking too much with knockbacks (unless you manage to manipulate the move order of your team to have Mai as the 2nd or 3rd before Julietta).