Successfully attacking enemies fills the gauge. The rate the gauge fills is determined by the strength of the party versus the enemies: the stronger the party is, the lower the rate at the start of battle. The rate steadily decreases by ten percent over the course of the battle until it reaches zero percent. Completely filling the gauge initiates a Bonus Battle, guaranteeing one of four bonuses after battle. The gauge breaks if the player character dies, receives a critical hit, or escapes from battle.