Common creatures are the foundation of the deck. Players can control multiple common creatures with the same name on the field. Generally, only common creatures can join a legion.
Players can control multiple advanced creatures with the same name on the field, but they cannot join a legion.
Hero creatures are the core of the deck, and are well-known figures in the world of Thrones. Only one hero creature with the same name can be controlled by the player on the field. Hero creatures can lead legions as generals.
The player can only have one legendary creature on the field, and only carry one in the deck.