Keyblade

The Keyblades (キーブレード) are mysterious weapons that are heavily featured in the Kingdom Hearts series. Wielded by the main character, Sora, as well as a number of other important characters, the Keyblade is a main part of the battle between Darkness and Light.

Development
According to an interview with Tetsuya Nomura, the original weapon shown during development was actually a chainsaw-like weapon. This was eventually scrapped in favor of the Keyblade.

Kingdom Hearts Birth by Sleep
Kingdom Hearts Birth by Sleep features eight people who can wield Keyblades: Ventus, Aqua, Terra, Master Eraqus, Mickey, Master Xehanort, Vanitas, and Yen Sid. Near the end of the game, Master Xehanort explains to Terra, Aqua, and Ventus that the Keyblades at Keyblade Graveyard are the remains of the Keyblade Wielders after the Keyblade War between the battle of Light and Darkness.

Terra also performs the Keyblade Inheritance Ceremony on Riku, passing the ability on to him. Aqua also does this accidentally with Kairi.

Ventus unintentionally gives Sora the ability to wield the Keyblade as well when the two boys join hearts at the end of the game.

Kingdom Hearts
When the worlds first started to disappear, King Mickey realized that Kingdom Hearts was going to be opened, and went to the Realm of Darkness to find its Keyblade, with which he could seal the door. However, he would also need someone to use a Keyblade from the Realm of Light in concert with him, so he left a letter for Donald Duck and Goofy, asking them to find the chosen wielder of that Keyblade and assist him in saving the worlds.

When the Heartless invade Destiny Islands, Sora rushes to the small island to save his friends, but finds that Kairi and Riku have already been swallowed by darkness. It is at this point that the Keyblade which Terra had promised Riku finally appears on the island, but because Riku has already given himself to darkness, the Keyblade falls to Sora's ownership.

Sora uses this Keyblade to seal the Keyholes of the worlds he visits, but when he arrives at Hollow Bastion, Riku reveals that the Keyblade was intended for him, and takes it back as Sora's heart falters. However, Sora soon confronts Riku, and the strength of his heart proves greater than Riku's, allowing him to steal the Keyblade back.

Confused and angry, Riku runs off and is found by Ansem, who convinces Riku to give Ansem his body in exchange for more power. This new "Dark Riku" summons the Keyblade of People's Hearts from the Princesses of Heart, in order to unlock the Final Keyhole, but it remains incomplete due to it lacking Kairi's heart. When Sora tracks down Dark Riku and confronts him, Dark Riku reveals that Kairi's heart is in fact within Sora, and attacks Sora in order to steal it. Sora defeats Dark Riku, but in order to restore Kairi's heart and fully seal the Final Keyhole, he uses the Dark Riku's Keyblade on himself, completing the keyhole and restoring all of the Princess's hearts at the cost of his body and soul.

Later on, after Sora, Donald, and Goofy defeat Ansem and attempt to close the door to Kingdom Hearts, King Mickey finally reappears with the Kingdom Key D, the Keyblade of the Realm of Darkness that he had gone to search for. With their help, as well as that of the restored Riku, they close the door, saving the worlds from the imminent flood of darkness.

Kingdom Hearts: Chain of Memories
Marluxia planned to use Naminé to enslave Sora through his memories so he could use the Keyblade against the rest of Organization XIII.

Kingdom Hearts 358/2 Days
Both Roxas and Xion are used by the Organization to collect hearts from Emblem Heartless using their Keyblades.

Kingdom Hearts II
Sora, Riku, Kairi, Roxas, and King Mickey can use the Keyblade. Sora uses the Keyblade to open new paths to new worlds through Gates.

Kairi's use of the Keyblade is limited to the Heartless surge in the Castle That Never Was.

Kingdom Hearts coded
Data Sora can use his digital version of the Kingdom Key to fix the World source of Bug Blocks and to seal the data keyholes. His digital Keyblade was destroyed in Episode 5, but gained a new Keyblade in Episode 6. King Mickey explains that this Keyblade is tightly connected to the Power of the Heart, implying that his Keyblade is genuine.

King Mickey also uses his own Keyblade to defeat the Heartless that attack his castle.

Powers
As the name implies, in combat, Keyblades are used in a manner similar to swords. Despite the fact that most possess no actual cutting edge, Keyblades still make efficient combat weapons and are shown to be particularly effective weapons against Heartless, Nobodies, and Unversed. However, as a downside to this, the Heartless use the Keyblade as a homing beacon, and thus Keyblade wielders are at constant risk of Heartless attacks at any time.

Most Keyblade wielders are also able to extend their Keyblade's length with Light or Darkness for their ultimate attacks. This has been seen for Sora's Ars Arcanum, Roxas, Xion and Riku's Limit Break in Kingdom Hearts 358/2 Days, Sora and Riku's Limit, Eternal Session, and Terra and Aqua's Command Style, Blade Charge.

The main power of the Keyblade, however, is the ability to seal or open the barriers between worlds, as well as to "lock" a world's Keyhole, preventing the Heartless from attacking that world's heart. As an offset of this ability, the Keyblade can also be used to lock or unlock any lock, allowing the user to access any sealed interior, whether it be a locked room, gate, or treasure chest. The Keyblade opens and shuts locks by emitting a bright, thing beam of light; this can also be used as an attack against certain enemies, although it is not featured in general game-play.

In addition to its base powers, it is possible to modify a Keyblade's appearance and powers by attaching various Keychains or Gears in the wielder's inventory. However, there are many Keyblades that do not possess a keychain for reasons unknown. There are other instances of the Keyblade changing form, such as when Riku's Soul Eater becomes the Way to the Dawn and when Roxas's two Kingdom Keys transmute into the Oathkeeper and Oblivion, but the mechanism behind these transformations is uncertain.

Inheritance requirement
The Keyblade has a special power that only lets a chosen wielder hold it. This is proven when Sora gives his Keyblade to Jack Sparrow only to have it come back to his hand. In the final battle with Xemnas, Sora was able to hold Riku's Keyblade and the same goes for Riku with Sora's Keyblade.

While there are many qualities a Keyblade wielder must have, the only known requirement is that they have an exceptionally strong heart.

It is implied in Kingdom Hearts Birth by Sleep that it is possible for a Keyblade Master to choose a person as their successor if they have the main qualities that allow them to hold a Keyblade, as Terra chose Riku to be his successor. Kairi seems to have inherited the same ability when she accidentally touched Aqua's Keyblade. Aqua originally considered choosing Sora to be her successor, but decided against it because Terra had already performed the ritual on Riku and she did not want the two to fight as she and Terra would. However, Sora nonetheless gained the ability to use the Keyblade when Ventus's heart fused with his own.

Keyblade Glider
In Kingdom Hearts Birth by Sleep, Terra, Ventus and Aqua have the ability to turn their Keyblades into vehicles and use them to travel to other worlds. This ability has only been demonstrated by the trio, though Master Xehanort explains in his Xehanort's Report that he used them during his own apprenticeship.

Magic
Keyblades are natural conduits for casting magic, as seen when Sora uses his Keyblade to command his magical attacks. This is not to say, however, that magic cannot be performed by a Keyblade Wielder when they are unable to summon their weapon. Some Keyblades have the innate ability to enhance specific kinds of magic, and many also augment the user's magical abilities on a more general level. Keyblades can also augment the holder with other powers and abilities that they would not normally be able to use.

Synch Blade
Keyblade wielders are also able to wield a second Keyblade using the Synch Blade ability. After Roxas defeats and absorbs Xion, he uses this ability at almost all times, generally with the Oathkeeper and Oblivion Keychains, while Sora only uses this ability while in his Valor, Master, or Final Drive Forms; however, Tetsuya Nomura has confirmed in interviews that Sora is able to dual-wield Keyblades in his base state, as Sora and Roxas share all of the same abilities.

Riku also exhibits this ability when he and Kairi meet up at The Castle that Never Was, and he hands a second Keyblade to Kairi to allow her to help protect Sora. Keyblade wielders are also able to allow others to wield this second Keyblade, or have it taken by the other wielder. When Roxas encounters Riku at Memory's Skyscraper he throws his Oblivion at Riku. Riku catches it and actually wields it in battle against him; when Roxas and Sora fight within the Awakening, Sora is able to steal Roxas's Keyblades and use them against him, though only temporarily.

Appearance
All Keyblades shown have the same distinguishing features that are modeled after a key: a guard with a handle, a hilt and a head at the end of the shaft that resembles the teeth of a skeleton key (with the exception of Fenrir, which is instead modeled after a pin tumbler lock key). Most Keyblades also have some theme, usually a world or a person associated with that world, that will reflect in its appearance.

History
The origins of the Keyblades is, thus far, unclear. Each game references the special qualities of the wielders and some give vague explanations of the Keyblades' power, but none have shown where the Keyblades originated, how they are created, or what their original purpose might have been. One legend mentioned in Kingdom Hearts states that the Keyblade master saved the world, while another said he wrought chaos and destruction upon it. While these legends may appear to contradict themselves, it can be assumed that the Keyblade master chooses how to use the Keyblade, whether for good or evil. The Keyblade is known throughout the worlds as a unique and powerful weapon. In Atlantica, King Triton and Ursula both knew of the Keyblade and its powers. King Triton did not want Sora to seal the Keyhole because he thought that the Keyblade would send his world into chaos, while Ursula knew that it gave the ability for the one who wields it to travel around the worlds.

One of the pieces of text in the hidden ending video for Kingdom Hearts II, "the Gathering", mentions a Keyblade War. Hundreds of Keyblades can be seen stuck into the ground during this cinematic, as well as the extended "Birth by sleep" cinematic at the end of Kingdom Hearts II Final Mix. It should be noted that none of these seemingly abandoned Keyblades, nor those of protagonists Aqua, Terra or Ventus, have Keychains, although the significance of this detail is currently unknown as the history of the Keyblades is unknown and the trio have been shown later to have Keychains attached to their Keyblades in Kingdom Hearts Birth By Sleep. Master Xehanort also stated that the thousands of Keyblades left are the ruins of the Keyblade War.

Keychains
Sora's Keyblade is known as the "Keyblade of Worlds' Hearts", and nearly all of his Keychain tokens represent some important item from a world he has saved. Usually, Sora is not actually shown to be given the Keychain from one of his many friends, so it is possible that after saving a world, or completing a major step in that direction, the world itself rewards him with the ability to access its power in the form of a unique Keychain.

Keychains that Sora receives from his friends, or from defeating challengers in the Olympus Coliseum, always use a token that is somehow intimately symbolic of that person. While Sora's Keyblade is not specifically a Keyblade of human hearts, like the explicitly named Keyblade of People's Hearts, it is likely that the connections between his heart and those he meets allow him to sometimes access their power as well. Sora and Roxas's Oathkeeper and Oblivion are said to specifically embody Sora's memories of Kairi and Riku and Roxas's oath to Xion before her death (Oathkeeper) as well as her demise (Oblivion) and so it is extremely likely that for "people-Keyblades" like these, the Keychains act as a physical embodiment of the memories Sora and Roxas has of those that are important to them.

In Kingdom Hearts 358/2 Days, Roxas utilizes Gears, which function more or less exactly the same as Keychains would.

Prominent Keyblade wielders

 * This is a list of the Keyblade wielders most important to the storyline of the series. For a complete list, see List of Keyblade Wielders.

Sora
The most prominent character in the series to use a Keyblade is Sora, who has used them successfully in the two main games in the series (with one minor incident). His ability to use and possess the Keyblade was a major plot point in the first game. He has used more Keyblades than anyone else in the Kingdom Hearts series; the variations are created through various keychains attached to his original blade, the Kingdom Key.

King Mickey
The King of Disney Castle, King Mickey's Keyblade is known as "Kingdom Key D". It looks the same as Kingdom Key, but its colors are inverted compared to the Kingdom Key. In Kingdom Hearts coded and Kingdom Hearts Birth By Sleep, he uses the Star Seeker, the Keyblade he used in his days as an apprentice under Yen Sid.

Riku
Sora's best friend and rival, he wields the Way to the Dawn Keyblade, though in Kingdom Hearts he briefly took possession of Sora's Kingdom Key. In Kingdom Hearts, he stayed behind with King Mickey in the Realm of Darkness. In Kingdom Hearts: Chain of Memories, he explores the basement of Castle Oblivion and struggles in resisting the darkness in his heart, Ansem, Seeker of Darkness, while in Kingdom Hearts II, he helped Sora defeat Xemnas. In Kingdom Hearts: Chain of Memories and Kingdom Hearts, he used the Soul Eater as his main weapon until it transformed into the Way to the Dawn Keyblade.

Roxas
Sora's Nobody and the thirteenth member of Organization XIII, Roxas also possesses the ability to wield the Keyblade, an ability which Xemnas uses to his advantage by ordering Roxas to gather countless hearts to complete Kingdom Hearts itself. Upon the absorption by Roxas of his Replica, Xion, Roxas regains the ability to wield the two Keyblades, Oblivion and Oathkeeper, an ability passed onto Sora when Roxas fuses with him.

Terra, Aqua, and Ventus
Three Keyblade wielders before Sora, apprentices under Master Eraqus. Sharing a common foe, Master Xehanort, they each suffer horrific fates due to Xehanort's doing at the end of the game: Terra is possessed by Master Xehanort and becomes the new Xehanort who becomes Sora's archenemy; Ventus is rendered comatose after his heart is damaged following a victorious confrontation with his dark side, Vanitas; and Aqua is stranded in the realm of darkness. All three currently await for Sora to rescue them from their fates.

Xehanort
The primary antagonist of the entire series. As his original persona, Master Xehanort, Xehanort is a Keyblade Master with plans to unleash the secrets of the Keyblade War onto the worlds and engulf the universe in darkness. To this end, he steals Terra's body by transferring his heart into the latter's body and becomes the new Xehanort, much younger and agile, combined with the ability to wield the Keyblade with both Master Xehanort's and Terra's powers. However, following confrontations with the Lingering Sentiment and Aqua, he loses his memories, except for his name, thus losing his ability to wield the Keyblade, as his Heartless, "Ansem", is shown using a double-ended version of Riku's Soul Eater, and his Nobody, Xemnas, uses Ethereal Blades in battle.

Trivia

 * In Kingdom Hearts, the Keyblade disappears until Sora starts attacking, while in Kingdom Hearts II and Kingdom Hearts Birth By Sleep, it reappears as soon as the player approaches an enemy. In Kingdom Hearts 358/2 Days, the Keyblade appears when Roxas takes damage. In the manga, Sora keeps his Keyblade behind him, strapped to his belt.
 * Each Keychain has a unique animation for when the Keyblade is summoned, and these animations usually symbolize a specific aspect of its respective Keyblade. For example, when Oblivion is summoned, a dark aura and violet sparks surrounds Sora's hands before the Keyblade actually appears. The particle effects that appear when the Keyblade is used to hit something also change with each Keychain. For example, the Keyblade "Two Becomes One" uses black and white checkered crowns when a solid object is hit.

Notes and References
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Keyblade Schlüsselschwert