How do you beat megadragonbowser?

The best way I can think of is killing enemies other than mega dragon bowser first this includes lava Valkyries, bucklers and smashers first. Because if I do megadragonbowser first than enemies on battlefield will just keep hitting the heroes until they are dead. Also avoid cover blocks and black char spots in the 2nd round because megadragonbowser breaths fire on those spots.In the 3rd round stay behind black blocks and avoid being close to a lava smasher because when megadragonbowser uses a shell and hit a black block he can’t use his shield until the next enemy turn when he does not hit a black block.