Answer:
Boss: Evrae
HP: 32,000, AP: 5400, Steal: Water Gem
Ok, this will not be easy. Everyone needs to have at least 1700 HP, so fight random battles on the airship if you need to. Begin by going in with Auron, Tidus, and 1 last guy, and heading into the fight with full Overdrives. Unleash your overdrives on him, and keep attacking. When all overdrives are exhausted, use Tidus, Auron and Rikku. Have Tidus and Auron continue attacking and have Rikku use an Al Bhed potion whenever someone is petrified or poisoned. When Evrae goes down to 8000 HP, he casts haste. Have Tidus cast haste on everyone before you nail the 8000 HP mark. When Evrae inhales air, it's going to use Poison breath the next turn. Have Rikku use an Al Bhed Potion before and after the attack. Keep it up, and Evrae will hit the floor hard. They key to the battle is have everyone hastened, have Rikku use Al Bhed Potions, and have everyone at least at 1700 HP to survive the Poison Breath.
message me at brycewalding2010@gmail.ocm if u need anymore help