353.1.a. If a card allows a player to play a card "ignoring its cost," its base Energy cost and base Power cost are set to zero.
353.1.b. If a card instructs a player to play a card "ignoring its Energy cost" or "ignoring its Power cost," only the appropriate cost is set to zero, and the remaining cost still applies.
353.1.c. Further additional costs and/or cost increases applied in subsequent steps may raise the card's Total Cost above zero. Example: Legion Rearguard is a Fury unit that costs 2 Energy and 0 Power and has Accelerate. A player plays Legion Rearguard and is instructed to ignore its costs, but chooses to pay the Accelerate cost. They ignore Legion Rearguard's Base Cost of 2 Energy, but the optional additional cost of 1 Energy and 1 Fury Power is added to its Total Cost and must be paid.