Whenever an opposing player plays a Clash card, that player adds a Doubt to another Clash card they control with a Doubt on it. If they don't, add a Doubt to the Clash card they control with the highest cost.
At the start of the Boss turn, each Clash card is dealt X damage, where X is the amount of Doubt on that card.
Opposing Clash cards get, "Trigger - Defeat: Move all Doubt from this card to another non-defeated Clash card you control".