The Battle Cats - Sin and Punishment 4*
You obviously don't need to stack Bahamut until the end of time, but the stage lets you do so very easily and it's a surefire way to beat it.
Treasures:
EoC : 300%
ItF Crystals : 600%
ItF Fruits : 300%
CotC Crystals : 500%
CotC Fruits : 0%
Recording app : Mobizen for Samsung