Only after the defeat of Feolthanos in Chapter 9 does Midlight's Deep become available for exploration. It consists of ten levels, between all of which the game may be saved, Espers rearranged, and Group Leaders switched in and outfitted with new equipment. The dungeon may also be left at any time, though the party must start back at the first level when reentering. On the tenth and final floor resides the superboss Yiazmat. After completing, Vaan's Anastasia sword also gets a boost of +10 in all stats. The stat boosts are cumulative if the player completes Midlight's Deep again.