From publisher's comprehensive rulebook: Heroclix ID cards show that a character on your force has a special contact within a larger organization that may be able to temporarily help. Many, but not all ID cards say they are “Unique”, and therefore only one ID card with that set symbol and collector number can be added to your force. When adding an ID card to your starting force, you must also add an associated ID character to your Sideline. [ID cards have a cost of 5.] Here is the text of ID cards: Inspiration: “A specific effect that varies from ID card to ID card.” Setup – At the beginning of the game, choose a character on your sideline with a name or real name matching this ID Card and turn it to a starting line. This character is called an ID Character. You can’t have more ID characters on your force than you have characters placed on the map at the beginning of the game. (If the card is Unique, it will say so here.) Call in Help – At the beginning of your turn, you may activate one ID Card per force. To activate an ID Card, choose a friendly character that has no action tokens and is equal to or more points than the ID Character's starting line. Give the chosen character a power action, place the ID Character adjacent to it, and then remove this ID Card from the game and your opponent scores it. The ID characters can’t be carried, given double power actions, replaced, or assigned resources. The ID character returns to your sideline immediately: (a) at the beginning of your next turn, (b) if it's not within 5 squares of the chosen character, or (c) if it is removed from the map by another game effect. Inspire – When a character friendly to an ID Character is in an adjacent square, they can use that ID Character's Inspiration.