I know this for a FACT because I was able to beat the final bosses two months ago, and I have added a 5 star and leveled all my 4 stars to max since then, and I was UNABLE to defeat the final bosses this time.
NOT. EVEN. CLOSE.
UPDATE (EDIT):
I apologize to the devs for my remarks. You guys were right, I was wrong.
I retried the level after watching a video and changing my tactics.
Here’s my solution:
I happened to have Boril hanging around idle, so I quickly ascended him to Tier 2 level 1, special at 3.
Lineup, left to right:
Falcon, Scarlett, Boril, Sartana, Melendor.
Items:
Arrows, healing vials, mana vials, bombs.
I had to use 75 gems to revive them ONCE, after Panther was dead. I focused Falcon and Scarlett on Panther instead of hitting all 3 bosses - DUH!
At the end, Owl and Kong killed themselves as I didn’t even get enough red tiles to fire Falcon or Scarlett for the last TEN TURNS.
Boril was the MAIN factor. And he was very weak. I just focused on keeping him and Melendor alive and charged. Timing was relatively important, and not wasting turns. Took my time and in the end it was actually kind of easy. Death blow was Owl exploding his special at me and then dying.
I DID use up ALL my items and at the end Boril and Melendor were dead but Owl hit Scarlett and Sartana and died because they were still sitting on Perfect Riposte.
Again I apologize to the Devs and the community for my immature outburst.
This game rocks!