For "The King of Destroyers" I use the Amazonian with her final weapon (you can see it in the weapon shop picture posted) and the skills boomerang, boomwhirl, and dash. The other skills are surge, mana, focus, and gold rush to make sure i always get 9999 gold. With those skills you can dash straight to the enemies in three seconds, use a boomwhirl before entering the hoard, and then boomerang spam