Finally I was able to put everything I grinded for into this fight (no name spoilers).
The First Heroine was defeated (but I would love to fight against all 3 of them at the same time. The only trouble would be survival because the Heroine almost killed my whole party.. I need to go to buy Goddess Teardrops to have a little safety.
Tried The 2nd and Third Hero and I wasn't able to survive 5 turns (dealt a total of 20k damage before I died) .. So this means that I need to train more.
At least the Mage is the weakest out of the 3 heroes due to not using Strongest attacks early.
2nd Hero defeated! This fight was tough from the very beginning to the end but luckily between each Instant Killing attack there were a few weaker attacks. Sadly I couldn't inflict Cure Couldron on the enemy more than one time.