For some action cards you will need to draw adversaries or allies cards. For example, if you draw an encounter card with two adversaries and one merchant in distress you will draw two cards from the adversaries deck and one card from the allies deck.
In space or sea allies are ships that can be treated as one player or the ship can have additional attributes gained from the characters within the ship. For example, a ship can have a cannon it uses for attack but, if a wizard is on board, the wizard’s magic can be used for attack as well. Adversaries can be characters, creatures, magic storms, anything that challenges the players.
It is useful to have two decks, one for allies, the other for adversaries. When building the decks you can craft the difficulty level depending on how great a challenge the player is seeking.