Skill or cloak? Let's go into more detail from this point...

The battle took place in the same turn, so there were no changes in the army or artifacts.
With Wave of Death, I eliminated the single-unit birds, finished off the angels with my hand (I had a cloak +2 speed), absorbed the implosion into the Bone Dragon, blinded the Medusas, and destroyed the Ballista. I raised the Bone Dragon and eliminated the Medusas with a ranged attack. It was good that the opponent didn't summon Earth Elementals in the first turn, but instead summoned the Implosion.