You can activate this card even if your opponent controls no monsters.
If no card is returned to the hand, no monster is destroyed.
"Hero Blast" targets 1 "Elemental Hero" Normal Monster in your GY.
You can activate "Hero Blast" when you opponent doesn't have any face-up monsters.
If the selected "Elemental Hero" Normal Monster is not returned to your hand, you cannot destroy 1 of your opponent's cards."