Successfully complete the indicated task to unlock the corresponding character in Mission mode.
Character
How to unlock
Donald
Reach Day 244 in Story mode.
Goofy
Reach Day 277 in Story mode.
King Mickey
Successfully complete the game, then purchase the Return Of The King item from the Moogle Shop.
Riku
Reach Day 171 in Story mode.
Sora
Successfully complete all missions (100% game completion), then purchase the Soul Of Sora item from the Moogle Shop.
Xion
Reach Day 96 in Story mode.
Challenge missions
Collect Ordeal Badges and Ordeal Blazons.
Defeating Dustflier
One of the requirements to fill the Mission Gauge of the "Kill At Least Six Giant Heartless" mission is to defeat Dustflier. This is the strongest Boss of the game beside Ruler Of Sky, Saix, Riku and Final Xion Form. Make sure to lock-on this Boss in combat and run quickly from it when it started to fly and stomp the ground. This move can kill Roxas with one hit, and cause status ailments or bad status. It has a large amount of HP and is immune to any magic -- be patient. Attack and run as you can, and make sure you can dodge all of the Boss' attacks. Equip the Zero Gear with two Ability Units, two Power Units, and one Guard or Magic Unit. Bring fifteen Megalixirs, five Cures, five Curas and five Curagas. If your level and stats are high enough, you should eventually win the battle.
Defeating Poison Plants
They are very weak to Fire elemental moves. Equip enough Fire magic in your panels slot. You may also bring some Potions.
Defeating Zip Slasher
Equip enough Potions on your panels slot, then start the mission "Collect Hearts in Twilight Town". In this mission you must kill all of the Dire Plants in the mansion area and defeat a strong heartless Zip Slasher in order to fill the mission gauge completely. After you eliminate all of the Dire Plants in the mansion area, get out from the woods. A caution sign will appear, stating that a strong Heartless is near. Defeat a weak Shadow in front of you, then go to the big alley (the entrance is between two houses) where the tram is stopped. Zip Slasher will appear. He has a high health, really defensive, and has a strong attack. He is also immune to Fire magic. Do not attack him first. Get away from him and let Marluxia slash him until he does his only attacking move, Spin and Stab (first he spins with his knuckles blades then stabs with his weapon). This is very fatal to your health if you are damaged by the move. After he does the Spin and Stab, he will start standing like a statue (not moving at all and probably recharging his attacks). Unleash a barrage of Keyblades slashing strikes until he starts guarding his body with his knuckles blades. When he does this, quickly run away from him. Make sure his attacks will not reach you, as he will do the Spin and Stab again. After he does his strike, attack him again with your keyblades and run away quickly from him when he starts to defend himself with his blades. Keep doing this until you win. Note: Do not waste your Potions. If Marluxia's health falls to 50%, he will use Curaga that will also heal you.
Dual-wielding Roxas
Successfully complete the game, then purchase the Zero Gear from the Moogle Shop. Equip it on Roxas in Mission mode then add three Ability Units. You can now dual wield with Roxas.
Free items from the organizations
Be sure to talk to every of the organizations in the Grey Area after you complete a mission. They may give you free items or quests to be done. If you complete the quests they give to you, sometimes they may give you rare items such as Diamonds.
Freebies items
Get the indicated number of crowns from completing missions in Mission or Multi-player mode. Select "Freebies" at the shop to get the corresponding item.
Successfully complete all Mission Mode missions with a "Gold Crown" rank to unlock the "Limit Pass" in the Moogle shop for purchase. This item allows you to customize limits in Mission mode.
Synthesis Moogle items
Collect the indicated amount of Sigils from the Holo-Mission challenges to unlock the following item from the Synthesis Moogle.