The Sea of Blood expansion allows players to take their Descent games to the high seas. New board sections include large expansive ocean tiles with scattered islands, as well as large ship decks with additional tiles featuring ships' cannons. The expansion includes an expansive overworld map featuring new sea areas and island locations to explore. The expansion also features new sea journey rules and adventures, as well as equipment and treasure cards and additional tuck boxes for packing the game away during longer campaigns.