Shiv

Shiv is a colorless special attack that deals 4 damage for 0 Energy and then Exhausts. It's not found in card rewards but is generated during combat by Silent skills like Blade Dance, Cloak and Dagger, and the Prepared relic. Shivs are the backbone of the Silent's Shiv build: with Accuracy equipped, each Shiv deals an additional 2 damage per stack; with Kunai or Nunchaku, playing multiple Shivs rapidly builds up Strength or Dexterity; and After Image generates Block for every Shiv played.

On its own, 4 free damage is modest but not negligible. In dedicated Shiv builds with Accuracy and multiple Shiv-generating sources, each Shiv can deal 10+ damage while building other stats simultaneously. The Exhaust means Shivs never clutter your deck long-term, making them purely beneficial in any quantity. Upgrading Shiv (via Apotheosis or smithing) increases damage by 2.