Keyblade Graveyard

The Keyblade Graveyard is a world that appears in Kingdom Hearts II Final Mix and Kingdom Hearts Birth by Sleep. It was first revealed in Kingdom Hearts II ' s secret ending, The Gathering. Before its formal introduction as a world, the Keyblade Graveyard is known as "The Badlands" (謎の荒野).

Settings and Areas
The Keyblade Graveyard is made up of unending, rocky, scarred by the battles of the Keyblade War. Early on, Terra and Ventus investigate the world at the Badlands (荒野), where they run into Master Xehanort and Vanitas, respectively. Later, the Vanitas Remnant and Lingering Will appear here, where they challenge intruders to battle.

Each of the heroes eventually enter the true battlegrounds of the world at the Seat of War (古戦場), a small outcropping of rock overlooking the shattered vista below. It leads into the Twister Trench (砂嵐の道), where literal storms of raw emotion roam freely. Within the Eye of the Storm (嵐の中) inside each twister, Unversed lurk, ready to attack all who are captured by the maelstrom. Past the storms is the Fissure (峡谷), a small ravine containing a save point and a Moogle Shop. The final area, the titular Keyblade Graveyard (キーブレード墓場) are two crossroads, covered by the Keyblades of the wielders who fell during the Keyblade War. During his battle with the heroes, Master Xehanort creates a pillar of rock from the graveyard, and summons Kingdom Hearts to shine down upon it.

After Master Xehanort steals Terra's body and is reborn as Terra-Xehanort, Terra's soul animates his armor as the Lingering Will, locks them both within the Will's Cage (思念の檻), and forces him into a final battle. Meanwhile, Ventus and Vanitas have reunited into Ventus-Vanitas, and Ventus is forced to fight off Vanitas's control within Ventus's Mind (ヴェントゥスの精神世界). Both of these areas vanish after the battle ends.

Kingdom Hearts Birth by Sleep
The Keyblade Graveyard is first appears when Master Xehanort calls Terra to meet him immediately. Upon reaching, Terra converses with Master Xehanort about the Unversed and the masked boy, Vanitas, who is the source of the Unversed, his origins and the danger he poses to the world. Master Xehanort informs him that Vanitas will attack Radiant Garden. Before Terra leaves, he is given instruction to "undo his mistake". Later, Ventus sees Vanitas floating through space, and follows him to question him on his earlier comment of Terra no longer being Terra. Ven once again visits the Keyblade Graveyard when he discovers that his friend and companion, King Mickey Mouse, has been abducted to the Keyblade Graveyard by Master Xehanort as to lure him into a trap. After explaining to the boy about his true purpose: create the X-blade, he sends Ventus and Mickey back to the Lanes Between. Master Xehanort then meets Terra who had just arrived and tells him to "save" Ventus from Eraqus's judgement. Later on, Vanitas appears before Ventus on Destiny Islands and reveals that he is the embodiment of the darkness inside Ventus's heart, and was created by Master Xehanort in the Keyblade Graveyard.

At the game's climax, through the manipulations of Master Xehanort, Terra, Aqua and Ventus each end up at the Keyblade Graveyard. Along the way, Terra and Ventus separately reached the site of Vanitas' creation, witnessing the Vanitas Remnant emerge. They fought him who attacked them with full strength. As he is defeated on each encounter, he drops the Void Gear and disappears into nothingness, leaving them to take the Void Gear. These encounters were actually Vanitas's last attempt to strengthen Ventus for both of them to clash in order to create the X-blade and destroy Terra and Aqua as they were in his way. Through this battle, Vanitas was successful in making Ventus stronger. The three Keyblade heroes meet up at the site littered with powerless Keyblades, discussing Eraqus's demise and Xehanort's true intentions behind his 'disappearance'. Master Xehanort appears alongside Vanitas, and explains to them that this was the place were a great battle took place, the Keyblade War, also revealing his intentions to use the χ-blade to unlock Kingdom Hearts and unleash the forbidden secrets of the Keyblade War upon the worlds. An epic battle ensues, and after Master Xehanort freezes Ventus and drops him off a cliff, Aqua catches Ventus's frozen body. Mickey later arrives at the scene. Terra regains his strength, heading towards the highest cliff and fights both Vanitas and Master Xehanort.

Meanwhile below, Aqua fights Braig, who mocks her on Terra's submission to his darkness to defend a frozen Ventus. After Braig escapes, Master Xehanort, still fighting Terra sends Vanitas off who knocked Aqua unconscious. After being hindered by the elderly Keyblade Master from saving his friends, Terra uses the darkness in his heart to fight Master Xehanort. In the meantime, Ventus thaws out and fights Vanitas who prepares to finish Aqua off. Afterwards, Vanitas who is about to fade away shows his true face, identical to Sora's, explaining the origins of the Unversed and his purpose of wreaking havoc in the worlds. He then forces Ventus to absorb him, creating a pillar of energy that knocked Aqua's unconscious body off the crater, signaling the X-blade's creation. In the meantime, Terra defeats Master Xehanort but after seeing the X-blade's creation as said by the elderly Keyblade master upon witnessing it, this allows Master Xehanort to take over Terra's body, thus creating Terra-Xehanort who discards Terra's Keyblade and Keyblade Armor and later muses on his 'birth'. As he prepares to leave, however, Terra's soul finds its way into his discarded armor, creating the Lingering Will who creates a cage that traps both him and Xehanort. Xehanort is enraged at Terra's mind resisting him, prompting the two to battle.

Meanwhile, Aqua regains consciousness and meets Mickey. They both encounter Ventus-Vanitas, as a result of Vanitas's union with Ventus, who reveals that Vanitas has possessed Ventus and muses on the the purpose of the X-blade he holds and Aqua and Mickey were forced to fight him. Both Ventus and Vanitas are transported to the merged Station of Awakening and fight their last battle. Vanitas is defeated in both fights and fades out of existence, and the χ-blade is destroyed, resulting with Ventus losing his completed heart. In the meantime, Xehanort is defeated, losing some of his memories. A huge blast created by the shattered χ-blade transports him to another world and Aqua and Ventus's bodies into the Lanes Between, where they are found and rescued by Mickey to be transported to the Mysterious Tower. The Lingering Will kneels down, and swears to Aqua and Ven that one day, he will end this conflict.

On the way to Radiant garden to save Terra from Xehanort's control after creating Castle Oblivion and the Chamber of Waking that housed Ventus's comatose body, Aqua sensed Vanitas's lingering spirit and heads to the Keyblade Graveyard once more. She enters the site of Vanitas's creation and fights him who attacked her with his full strength. As she defeats him, he drops the Void Gear, disappearing away. Picking up the Keyblade up, she leaves the desolate wasteland to continue her journey.

Kingdom Hearts II Final Mix
In Disney Castle, a portal to the Keyblade Graveyard appears in the Hall of the Cornerstone. Chip and Dale summon Sora, Donald, and Goofy, who enter the portal and find the Lingering Will alone in the Keyblade Graveyard. The Lingering Will first wonders if Sora is Aqua, Ventus, Riku or even Xehanort. Calling out Xehanort's name, the Lingering Will engages Sora in a fierce battle. Sora manages to defeat the Lingering Will, who respectfully acknowledges Sora as a true Keyblade Master and then returns to his normal position. If Sora comes back to challenge him again, the Lingering Will agrees to fight, but states to Sora that he has nothing left to give him save for his hatred for Xehanort.

Kingdom Hearts 3D: Dream Drop Distance
The Keyblade Graveyard appears in the game's opening FMV, in which Master Xehanort battles Sora, Riku, Terra, Ventus, Aqua, Roxas, Donald, Goofy, and King Mickey at night.

Trivia

 * The capital letters in the logo for the Keyblade Graveyard slightly resemble real Keyblades. The "K" bears resemblance to the teeth of the Earthshaker, the "E" resembles the teeth of the Wayward Wind, the "G" bears similarity to the guard of the Rainfell, and the final "D" resembles the guard of the Kingdom Key complete with the Keychain, albeit featuring Sora's Crown Pendant rather than a Mickey Head.
 * The "teeth" of Oblivion, Oathkeeper, Sleeping Lion, Follow the Wind, Circle of Life, and Fenrir, as well as the Keychain of Master Xehanort's Keyblade, can been seen coming out of the bottom of the World icon.

Notes and references
Necrópolis de Llaves Espada