Clash

Clash is a 0-cost Ironclad attack that deals 14 damage (18 upgraded) but can only be played if every other card in your hand is an Attack. The restriction makes it useless in mixed decks but extremely powerful in single-archetype attack builds. At 14 free damage, Clash outclasses almost every 1-Energy attack in the game when its condition is met, and at 18 upgraded it approaches rare-card power levels for no Energy cost.

The key to using Clash effectively is deck construction: avoid Skills and Powers, or use Exhaust effects to clear non-Attack cards from your hand. Pure aggro Ironclad builds that lean into all-attack compositions get tremendous value from Clash. It's a build-around card that rewards deliberate deckbuilding more than most commons.