Keyblade Armor

Keyblade Armor (鎧) is a suit of armor worn by Keyblade wielders. It is introduced in Kingdom Hearts II worn by Xemnas. One of its most important qualities is that it protects the wearer from the darkness surrounding the Lanes Between, much like the black coat and the good fairies' garments. However, it is also worn during battle, at the user's discretion.

Pieces of the armor usually appear as part of the user's normal clothing, such as their boots or belts. However, the armor's left is more important—by pressing it, the user activates the rest of the armor, which appears in a flash of light. Despite the fact that it usually appears and disappears magically, the armor can also be removed physically, as Terra-Xehanort did once he had gained control of Terra's body, and Aqua did to give Terra's body a vessel to take him out of the Realm of Darkness.

The armor can also act on its own to protect the user, should they be tossed to the Lanes Between unknowingly; Ventus was tossed to the Lanes by the Star Shard, Xehanort and the χ-Blade. In the third case, the armor is shown to repair the helmets immediately to provide air for the wearer. Despite its heavy appearance, the armor does not appear to impede movement in any way.

Development
In "The Gathering" and "", Terra, Ventus, and Aqua each have capes attached to their suits of Keyblade Armor, but these capes were removed in Kingdom Hearts Birth by Sleep due to frame rate issues. In Kingdom Hearts HD 2.5 ReMIX , during the final cutscene in Terra's story, the Lingering Will sprouts a cape, maintaining continuity between Kingdom Hearts Birth by Sleep and later appearances such as Kingdom Hearts II Final Mix and Kingdom Hearts III. All three Keyblade wielders' armors are also seen with capes in Kingdom Hearts III Re Mind.

stated in an interview that he chose to use armor to hide Terra, Aqua, and Ventus's yet-to-be-designed faces to avoid using the black coats of Organization XIII again. Nomura's decision was also influenced by the recent release of Final Fantasy XII, which featured the armored, as well as an early, canceled project of his.

In Kingdom Hearts Birth by Sleep, at the Mirage Arena, Terra, Ventus, and Aqua can change the hues of their armor.

Kingdom Hearts Dark Road
Master Odin teaches his students Xehanort, Eraqus, Vor, Urd, Bragi, and Hermod how to use their Keyblade Armor and Keyblade Gliders so they can travel between worlds and search for their seven missing upper classmates.

When traveling through the Corridors of Darkness, Xehanort decides to remove his Keyblade Armor, causing him to loose consciousness. Upon waking up, he is greeted by The Master of Masters, who explains that the black cloaks are far better at warding off darkness than the armor.

Kingdom Hearts Birth by Sleep
According to Xehanort's Report, Master Xehanort had once worn his Armor as instructed, but when he felt the darkness of the Ocean Between, he decided to embrace it, rather than avoiding it.

Terra, Ventus, and Aqua wear their Armor whenever they enter the Lanes Between, or when they land at the Mirage Arena. They also activate the armor when they are attacked by Xehanort at the Keyblade Graveyard.

When Terra defeats Master Xehanort in their final battle, the elderly Keyblade Master unlocks his own heart. Terra attempts to protect himself from Xehanort by quickly activating his armor, but Terra's darkness allows Xehanort to take control anyway. Terra's armor falls to the ground in pieces as the new, younger Terra-Xehanort walks off, but rises again as Terra's soul animates it. It creates the Will's Cage around the two, forcing Terra-Xehanort to turn and fight. It manages to knock out Terra-Xehanort, who is swallowed by the χ-blade's aura and transported to Radiant Garden. Its job done, it kneels down with its Ends of the Earth Keyblade in its hands, and remains there for the next eleven years.

After leaving Ventus in the Chamber of Waking and encountering a confused Terra-Xehanort at Radiant Garden, Aqua damages Terra-Xehanort enough for Terra's heart to temporarily take control and cause Master Xehanort to force Terra-Xehanort into stabbing himself with the No Name Keyblade, knocking his body out. Both Aqua and Xehanort fall into the Realm of Darkness. Aqua removes her armor, and instructs both it and her Rainfell Keyblade to take Xehanort back through the closing portal to Radiant Garden. Dilan later discovers the unconscious Xehanort and Aqua's armor, and Ansem the Wise instructs Braig to carry Xehanort, and Dilan to bring the armor back to the Hollow Bastion.

After Xehanort became Xemnas, he placed Aqua's armor within the Chamber of Repose, where he often went to speak to it. Xigbar eventually noticed Xemnas's conversations with Aqua's armor, and would bring it up to Zexion.

Kingdom Hearts 358/2 Days
When she fights Roxas, Xion dons a suit of armor that combines motifs from the Keyblade Armor, the Nobody emblem, and Sora's own clothes. At times, the armor also has wings, extra arms, or trailing ribbons that draw from Sora's memories, and a set of "Keyblades" which do the same.

Kingdom Hearts II
During the Battle of the 1000 Heartless, Xemnas visits Aqua's armor and Keyblade, addressing it as his "friend."

A portal to the Keyblade Graveyard appears at Disney Castle at one point, and Sora, Donald, and Goofy enter it to find Terra's Lingering Will. It first mistakes Sora to be Riku, and finally Master Xehanort, before attacking him in a great rage. Upon its defeat, the Lingering Will realizes it has attacked the wrong person, and respectfully acknowledges Sora as a Keyblade Master.

Xemnas dons Xehanort's Keyblade Armor while attacking Sora and Riku atop his Dragon Form. During this fight, Xemnas is also able to use the weapons of the recently destroyed members of Organization XIII.

Kingdom Hearts 3D: Dream Drop Distance
When Sora's heart is damaged while fighting Xemnas and Young Xehanort, it begins to fall into darkness. Ventus's heart, which rests within Sora's, summons Ventus's Keyblade Armor to shield Sora's heart from the darkness until it can be healed. However, by the time Riku enters Sora's heart, the armor has itself become immersed in darkness, transforming it into a Nightmare which uses Sora's body and Keyblade along with Ventus's own fighting style. The armor is destroyed by Riku after a long, grueling battle, and his victory was the deciding factor in his being named a Keyblade Master by Yen Sid.

Kingdom Hearts III
Following the Replica Xehanorts's defeat, Master Xehanort absorbs their essence to create a new Keyblade Armor before fighting Sora, Donald, and Goofy. After an arduous battle, the trio is able to destroy the armor.

After Sora rescues Kairi, the Replica Xehanorts fuse into a copy of Xehanort's armor, but are repelled and destroyed by the Guardians of Light.

Shortly after Master Xehanort’s defeat, Terra, Aqua, and Ventus decide to venture into the Realm of Darkness to find Sora, donning their Keyblade Armor before they departed.

Kingdom Hearts χ
In Kingdom Hearts x[chi], the s could earn a Keyblade Armor resembling their Union's design during the third Anniversary event.