Herald of War

A cost-reducer that manufactures its own discount by attacking, which is the wrinkle that separates it from the static reducers it resembles. A flat tribal cost-shaver pays out the turn it lands; this one starts at zero reduction and grows only when it swings. The engine is wired into combat rather than the cast step, but not into surviving combat: the attack trigger resolves before damage, so the counter (and the discount it enables) is banked the moment you declare it as an attacker. What the card asks for, then, is repetition. One swing shaves a single mana off the next Angel or Human; three or four counters deep, your top-end lands at a discount steep enough to fold two turns into one. Getting there means keeping a 3/3 flyer alive across multiple combats on a body that is not hard to kill, so the real clock is your own removal-exposure, not the swing itself. The narrow tribal restriction (Angel spells and Human spells specifically, two of white's deepest creature lines) is what keeps the reduction from spiraling: it accelerates only decks already built to chain those creatures, and the attack-trigger structure means it accelerates them one counter at a time. It rewards a curve that wants to keep deploying threats after it has already committed to the red zone, the inverse of the static reducer that wants you to hoard cards and empty your hand in a single turn.