Arcana Force XIV - Temperance (LODT-EN014) - Light of Destruction (2020 Date Reprint) Unlimited

During either player's turn, you can discard this card to reduce the damage you take from a battle to 0. When this card is Summoned, toss a coin: Heads: Halve all Battle Damage you take. Tails: Halve all Battle Damage your opponent takes.