Core Rules › 356 › 356.2Rule 356.2.a Mandatory Additional CostsMandatory Additional Costs356.2.a.1 Some Additional Costs specified by Passive Abilities on the card being played or another card are Mandatory, and must…356.2.a.2 The cost imposed by the Deflect keyword is a Mandatory Additional Cost. See rule 809. Deflect for more information.Official Core Rules