that includes "Elemental Hero" in its card name, negate 1 attack from your opponent's
Rulings for Hero BarrierYu-gi-oh! Card
You can activate this card at any time before the Damage Step. You can activate it before the opponent declares any attacks, but in that case the first attack your opponent makes will be negated.
"Hero Barrier" can be activated even if you do not have a face-up "Elemental Hero" monster on the field. If you do not have an "Elemental Hero" monster on the field when "Hero Barrier" resolves, then it does nothing. This means if the opponent chains "Ring of Destruction" to destroy your only "Elemental Hero", then "Hero Barrier" does nothing.
If you have a face-down "Elemental Hero" monster on the field, and you activate "Hero Barrier", when the opponent attacks your face-down monster and flips it face-up, the attack is not negated because it is already in the Damage Step.
If you activate "Hero Barrier" when your opponent attacks 1 of your monsters (and its not your only "Elemental Hero"), and the opponent chains "Ring of Destruction" or "Interdimensional Matter Transporter" to remove the attack-target monster from the field, a replay does not occur, because the attack is still negated by "Hero Barrier".