Mission 8-4 Wayward Soul [Submitted by: Cheat Masters ] At the bigining of battle, summon at least one rank 2 water type Esper. All enemies are weak against water. Try a rank 111 Esper like Mateus.
Now begin by closing off the 2 summoning gates on the right kiling enemies as you go along. When you get to the top gate you will fight Chaos. Use the spell Blizzaga and have Penelo cast Cure on your troops.
With that location seized, it should be easy to send a wave of fliers across the lava towards Mydia. Summon more fliers to attack her when the other opposition is suppressed.
It is important to know that Mydia will remain immobile as long as you do not approach her from the ground. Therfore, the fliers you use to mount the attack will pretty much defeat her without you having to worry about being counter-attacked!
Alternate Ending Description: Get an alternate ending How to: Beat the game with a 100% completion rating. Otherwise, you will get the standard ending if you beat the game with anything less than 100%.