The Heresy Game Engine uses a dice pool system for determining the outcome of any action a character attempts in the game. The player rolls a certain number of dice based on the relevant skill and attribute that relates to the action. Like other dice pool systems certain results are successes and some results will allow the player to roll additional dice.
One novelty of the HGE is the use of a 'Black Dice Pool'. These dice are rolled along with the standard dice pool. The more difficult the action the more Black Dice are rolled. Successes on the Black Dice cancel successes rolled in the standard dice pool.