The Ready Cost (in Power) required to play this card.
Power is the measure of your Mana Pool (EQ1) or Power Pool (EQ2). It is the blue bar on the left side of your Avatar. All Avatars start the game with 3 Power. All avatars gain 1 power any time any avatar completes a quest.
Most actions in the game require an expenditure of Power to Invoke the card. This Cost, if any, is shown in the upper-left hand corner of the card inside the Card Type icon.