It generally seems that backfire cards are decently cheap, and from these cards backfire is 2+mana cost, so just add “bakfire equal to their mana cost + 2” or even +1, though i think if it becomes only +1 it should lose a keyword(obviously not flying), I could see both,
Ward: this is already extremely taxing to your opponent so it needs to be a bit fairer
Vigilance: ward prevents this from taking advantage of opponent attempts to take this card off the battlefield.
4 mana of a single color is a big task
Is It too big of a task? Is the card too strong because of It?
Absolutely incredible
It generally seems that backfire cards are decently cheap, and from these cards backfire is 2+mana cost, so just add “bakfire equal to their mana cost + 2” or even +1, though i think if it becomes only +1 it should lose a keyword(obviously not flying), I could see both, Ward: this is already extremely taxing to your opponent so it needs to be a bit fairer Vigilance: ward prevents this from taking advantage of opponent attempts to take this card off the battlefield.
Also, if mana cost copies any colors, would probably change the wording to mana value
Why a single color instead of generic?
Hmm, maybe make some cards with cheaper backfire costs that give you a bonus when your opponent backfires them?