Defeating The Stratoavis In The Battle Arena
Once you collect all the monsters from the desert, go back to the Calm Lands and go to the Battle Arena. If you have caught all of them, the man will offer you a free fight with the new monster he just created. Accept his offer. Once in the battle, make sure you have Yuna in your party. Wakka and Tidus are also recommended. To make this faster you will need the Aeon Yojimbo. He can dodge all the attacks from Strutoavis and put Yojimbo in Overdrive. This should enable you to pay a low price for maximum damage. You should be able to pay 10 to 20 gil and he will do one of four attacks. If he does Wakizashi or Kozuka, it should do maximum damage. Do this about fifteen to twenty times and he should fall. You should get about 10,000 AP for winning, and perhaps a Key Sphere.