Each Build & Battle Box includes four Mega Evolution—Perfect Order booster packs and a 40-card, ready-to-play deck featuring key cards from current and prior expansions, as well as one of four unique foil promo cards. Depending on which promo card you get, you could be playing with the royal Serperior, the handy hero Barbaracle, the tyrannical Tyrantrum, or the sword-flashing Doublade.