Instructions
Defeat Feolthanos at the end of Chapter 9 to reveal the secret Midlight's Deep dungeon. Save your game and then touch the Midlight's Deep dungeon icon on the game screen to enter the level. Defeat all the enemies and destroy the Soul Crystal on Level 1 to move to the second floor.
Defeat the Malboros and the bombs on Level 2. Collect all the treasure items. Climb the stairs to the third floor.
Prepare to do battle with the War Chief. Ignore all other enemies. Select summon Chocobo for each of your characters. Press the "X" button. Tap the War Chief with the stylus and repeat until the War Chief is defeated. Defeat the remaining enemies and climb the stairs to Level 4.