An opponent is any other player in the game. However, the word opponent can be specific or general. Normally, when a single opponent is indicated, the player may select any other player and target him or his cards. “Opponents' ” or “each opponent” refers to all other players in the game.
During the Battle Phase, however, the specific “opponent”, “your opponent’”, or “opponent's” means the other player engaging you in battle. The general “an opponent”, “any opponent”, or “one opponent” can still be selected by the player.
Several cards in Redemption® refer to “opponent’s cards” (e.g., opponent’s Heroes). For a card to be considered an “opponent’s card”, that player must be the owner of the card as well as have control of the card.