Formchange is an ability first demonstrated in Kingdom Hearts II Final Mix, before being included as a gameplay mechanic in Kingdom Hearts III. Formchange allows the user to change their abilities or the form of their Keyblade. Formchanges are triggered via Situation Commands after achieving sufficient damage with a Keyblade. Certain Keyblades will also have the ability to Formchange a second time. Formchange is a mechanic that borrows cosmetic and technical concepts from Command Styles and Drive Forms both, and allows Sora to manipulate his Keyblade's form similar to the wielders from Kingdom Hearts Birth by Sleep.
Unlike Drive Forms, Formchanges do not carry over into cutscenes.
The concept of having the Keyblade transform into different forms has existed since Kingdom Hearts II Final Mix with the Lingering Will being able to transform the Ends of the Earth Keyblade into different forms. The idea was to incorporate it into Kingdom Hearts III's gameplay to show the growth of Sora's skill as he trained and become a more masterful Keyblade wielder.
Guardian Form and Strike Form were originally referred to as Guard Form (ガードフォーム, Gādo Fōmu?) and Power Form (パワーフォーム, Pawā Fōmu?) in early gameplay notes and were considered Drive Forms before the formal introduction of the Formchange concept.
List of Forms and Formchanges
Second Form allows Sora to access his abilities from previous adventures, similar to Limit Form. The color scheme of Sora's clothing changes to resemble his Kingdom Hearts II outfit. It is triggered by the Kingdom Key, Starlight, Midnight Blue, Phantom Green, and Dawn Till Dusk. The Keyblade used determines the third level finisher: Starlight uses a finisher called "Ancient Light", which draws enemies in before releasing several Keyblades made of light to strike them, while the others use Ars Arcanum instead.
Rage Form allows Sora to channel his darkness in desperate circumstances. Sora takes on the appearance of a Pureblood Heartless, similar to AntiForm. It has a chance of being triggered when Sora reaches critical health, regardless of current Keyblade. After using the command Risk Charge, Sora will gain extra strength at the expense of half his current health.
Ultimate Form unleashes the ultimate power of the Keyblade. Sora wears white clothes reminiscent of Final Form. Triggered by Ultima Weapon. While attacking, Sora will summon a variety of swords that will surround him and will be used in finishers, he uses a pattern of magic and uses the symbolism of chains during some attacks.
Double Form allows Sora to harness light and darkness together. Triggered by Oathkeeper and Oblivion. When attacking, Sora dual-wields both Keyblades in a manner similar to Roxas.
Spellweaver is a Formchange exclusive to Aqua during her playable segments. Triggered by Master's Defender. It behaves almost exactly like the Style Change from Kingdom Hearts 0.2 Birth by Sleep -A fragmentary passage-, except the Finish command is available upon activation, like Sora's Formchanges.
Kingdom Hearts II Final Mix
Kingdom Hearts Birth by Sleep
Terra, Aqua, Ventus, and No Heart can Formchange their Keyblades into the Keyblade Glider. Terra can Formchange his Keyblade into the Ultima Cannon, which Terra-Xehanort inherits. No Heart can also Formchange its Keyblade into a myriad of weapons such as greaves and a shield.
Kingdom Hearts 3D: Dream Drop Distance
Kingdom Hearts III
Lea can Formchange his Keyblade Bond of the Blaze into his Eternal Flames Chakrams. Young Xehanort also Formchanges his Keyblade into a whip during the fight against him, Xemnas, and Ansem, Seeker of Darkness. Master Xehanort can Formchange the χ-blade into several transformations, such as a whip, chakram, or dual-sided blade
When fighting Terra-Xehanort, the Lingering Will Formchanges its Keyblade into a whip and the Ultima Cannon.
Kingdom Hearts III Re Mind
The data replica of Young Xehanort can Formchange its Keyblade into a whip, and Master Xehanort can Formchange the χ-blade into several transformations, such as a whip, chakram, or dual-sided blade.
Notes and references