Forever Kingdom is the prequel to Evergrace set directly before those events. The player controls Darius (the main character), Ruyan (the childhood friend), and Faeana (the amnesiac). While traveling the party comes upon a strange girl named Solca, who is summarily kidnapped by an evil wizard named Darsul. During that event, the party is cursed by Darsul, and they now share 1 life bar.
Battles occur in real-time, and the player can freely switch controls to any of the three characters. Skills are gained through equipping items. Each character is assigned a button and can use their skills by pressing that button. Using multiple skills from each character can result in combos that give bonus damage.