Instructions
Go to the Monster Arena in the Calm Lands. The arena is located along the eastern stone wall. There is a crack in the wall that leads to the entrance of the arena.
Talk to the man at the door. He will explain how the Monster Arena works. Purchase capture weapons from the man and equip them to the characters.
Leave the Monster Arena. Wander around until your party begins a battle. Fight the enemies in the battle. When a character with a capture weapon gives the finishing blow, the enemy will be captured.
Capture every enemy in an area. For example, capture one of every enemy in Besaid. They are the Dingo, Condor and Water Flan.
Travel to five more areas and capture one of every enemy in the area. Each area has specific enemies found nowhere else in the game.
Return to the Monster Arena in the Calm Lands after you have captured one of every enemy from six areas. Talk to the man and he will tell you that you unlocked six area creations in the Monster Arena. You are awarded 99 Doors to Tomorrow. You can fight the creations you unlocked in the Monster Arena.