Unlockable: Whyt Summon Types
To customize the way Whyt looks (Whyt being a special customizable summon spell available to Rydia), fulfill the requirement listed for any given option.

Black Mage - Maximize your score in Rydia’s minigame
Dragoon - Maximize your score in Kain’s minigame
Goblin - Complete the game once through in its entirety
Ninja - Maximize your score in Edge’s minigame
Paladin - Maximize your score in Cecil’s minigame
Summoner - Maximize your score in Rydia’s minigame
White Mage - Maximuze your score in Rosa’s minigame
Zeromus - Fill your in-game bestiary completely

Hint: Cheat at Rydia's Minigame
Rydia’s minigame is one that depends on speedily getting through math problems. If you close your DS after grabbing the four numbers you have to work with, however, the game will go to sleep, essentially freezing the time spent. Grab a pen and paper and write the numbers down. Work out the math, and once you’ve figured it out, flip the DS’ lid back up. Quickly insert the necessary answers, grab the next four numbers, shut the lid, and repeat. This will get you the maximum 9,999 point score.