At the start of a duel, each player is granted 64 HP. The goal is to get the opponent's HP to zero through turned based combat. Souls are used as currency to summon spirits from pages (cards) within a tome (deck), built before the match. Every card is unique, so there are tons of combinations of abilities. Not only are the cards unique, but the tome that carry them have special abilities as well. The soul-gathering is actually different for every tome, so matches will be extremely varied.