Bronze Scales
Bronze Scales is a common relic that deals 3 damage back to any enemy that attacks you. This retaliation applies every time you are hit, regardless of how much damage you took. It is a passive form of damage that does not require energy or cards to activate and accumulates across all attacks an enemy makes against you throughout a fight.
Bronze Scales is strongest against enemies that attack frequently in small hits, since each individual attack triggers the 3-damage retaliation. It is less effective against enemies that hit once for large amounts. The relic has particularly interesting synergy with cards like Flame Barrier (which deals its own retaliation damage) and builds that intentionally take hits to proc effects. Bronze Scales falls off in value at higher ascension levels when avoiding damage entirely becomes critical, but in standard runs it can whittle down enemies for free, occasionally killing weaker foes without spending a single card.