The Casting Shadows expansion adds two new playable characters and three additional hex tiles, increasing the maximum player count to six on an expanded game board. New gameplay mechanics allow players to freeze and stun opponents, restricting their movement and resource management. The expansion includes 34 cards, 3 hex tiles, 10 status tokens, 2 double-sided player boards, 2 meeples, 1 hex tile reference sheet, and 1 rulebook. The base game is required to play, and the expansion supports 2 to 6 players.