Quote Originally Posted by Tavrobel View Post
Monster Arena for Catoblepas (Area) and Shinryu (Original).

The Aeon's Soul is found by defeating Begemine your first visit to the Calm Lands, by the Agency. Regardless of the outcome of the battle, you will receive the Aeon's Soul.

Suffice it to say, you won't be getting Doublecast on Shiva any time soon.
You should be able to get 5 Three Stars by playin Blitz also....just resetting until it is offered as a prize.