Editing Castle Oblivion

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{{Youmay|the World|{{c|Castle Oblivion|track|the field theme}} or [[Card 01: Castle Oblivion|the chapter in the ''Kingdom Hearts Chain of Memories'' manga]]}}

  |romaji=Bōkyaku no Shiro

'''Castle Oblivion''', often abbreviated as "'''C.O.'''" by members of [[Organization XIII]], is a world introduced in ''[[Kingdom Hearts Chain of Memories]]''. It is located within the [[Realm Between]], and a digital copy of the world appears in ''[[Kingdom Hearts coded]]''. It was governed by [[Marluxia]], and consists of thirteen floors and twelve basements. After Marluxia's defeat, the Organization abandoned the castle as they lacked the manpower to keep it operational.

Castle Oblivion was originally the [[Land of Departure]]. Hidden within the castle is the [[Chamber of Waking]], where [[Ventus]] sleeps; no one but [[Aqua]] can locate the Chamber, as she was the one who locked the castle to keep Ventus safe. Castle Oblivion is restored into the Land of Departure following Aqua's rescue from the [[Realm of Darkness]].

Castle Oblivion is a mystical castle found at the end of passage floating in the middle of nowhere. It is located within the [[Realm Between]], surrounded by dark clouds with faint lights piercing through far behind. The castle has an uneven and twisted design with towers pointing in all directions. Some even stick out from underneath the road. The outside is a dark gold with turquoise roofs, while everything on the inside is generally white. The interior is implied to be incredibly vast, to the point one would get lost in it, as was the intention of Aqua; the Organization compensate by using Dark Corridors. Axel has complained that searching the castle is next to impossible, stating it's "like counting grains of dust in a room of sneezing people".

===''Kingdom Hearts Chain of Memories''===

The interior of Castle Oblivion consists of simplistic white marble architecture with infrequent plinths, wall-carving, and sculptures made with a flower motif. It is divided into many '''{{a|White Room}}s'''{{?}}<!--cite the reports--> which are shaped by the memories of those exploring them through the use of [[World card]]s and [[Map card]]s; though this second part may be due to the Organization's experiments with memory.  Between each of the White Rooms is an {{nihongo|'''{{a|Entrance Hall}}'''|入口ホール|Iriguchi Hōru}} and {{nihongo|'''{{a|Exit Hall}}'''|出口ホール|Deguchi Hōru}} for each of the thirteen floors and twelve basements. The Entrance Halls contain "{{a|World Warp}}s" which allow quick travel between the floors. The walls of the hallways have a yellow gradient near the top in the original ''Kingdom Hearts Chain of Memories'' while also having light blue colors contrary to the more pale colors in the remake. The castle also contains a {{nihongo|'''{{a|Pod Room}}'''|ポッドルーム|Poddo Rūmu}}, housing the [[pod]]s within which Sora, Donald, and Goofy were put in hibernation.

Somewhere among the thirteenth floors is a meeting room the Organization uses to discuss plans, as well as monitor the other floors via a crystal ball. This is also where Naminé is kept prisoner. The basement also has a meeting room which is dimly lit, almost appearing to be blue in color, and usually where Zexion can be found.<!--Zexion is always the first to show up here, so it stands to reason this is where he "observes" scents of darkness--> Vexen also has an unseen laboratory where he works on the [[replica]] project.

Battles against most Organization members in ''Kingdom Hearts Re:Chain of Memories'' and the [[Riku Replica]] transport Sora and Riku to an arena within some sort of pocket dimension called {{nihongo|'''{{a|Station of Remembrance}}'''|追憶の園}}. The arena consists of a circular, grey, and decorated floor, hanging in the air, with four pillars surrounding the platform. In ''Kingdom Hearts Chain of Memories'', the members are fought within the hallways instead. Marluxia's second form is also fought in sort of pocket dimension - accessed from the thirteenth floor - called {{nihongo|'''{{a|Station of Oblivion}}'''|忘却の園}}. The arena is similar to the Station of Remembrance, though it's a lot bigger and the room is a lot brighter. His Radiance of Darkness technique allows him to temporarily turn the skies dark and starry. In ''Kingdom Hearts Chain of Memories'', the final battle against Marluxia takes place in a starry sky-like void instead. In the remakes, the third and final Marluxia battle takes place in a dark and blue sky void as well, and on top of what appears to be the remains of the specter from the previous fight turned giant.

In ''Kingdom Hearts II Final Mix'' Castle Oblivion's {{nihongo|'''{{a|Station of Remembrance}}'''|追憶の園}} serves as a boss arena for both of [[Lexaeus]] and [[Larxene]]'s [[Absent Silhouette]] and [[Replica Data]] battles. The {{nihongo|'''{{a|Station of Oblivion}}'''|忘却の園}} also makes a return for [[Marluxia]]'s Absent Sillhouette and Replica Data fights.

In ''Kingdom Hearts Re:coded'', Castle Oblivion appears as a data recreation within the [[Datascape]]. Data-Sora arrives at the castle's {{nihongo|'''{{a|Entrance Hall}}'''|入り口ホール}}, where Data-Roxas will allow access to five separate white chambers modified to match the basic layouts of {{nihongo|'''{{a|Destiny Islands}}'''|デスティニーアイランド}}, {{nihongo|'''{{a|Traverse Town}}'''|トラヴァースタウン}}, {{nihongo|'''{{a|Wonderland}}'''|ワンダーランド}}, {{nihongo|'''{{a|Olympus Coliseum}}'''|オリンポスコロシアム}}, {{nihongo|'''{{a|Agrabah}}'''|アグラバー}} and {{nihongo|'''{{a|Hollow Bastion}}'''|ホロウバスティオン}}. Images from each world appear in poster-esque fashion across the walls.

 

Data-Sora battles Data-Roxas in the {{nihongo|'''{{a|Station of Sorrow}}'''|悲しみの園|Kanashimi no En}}, which is identical to the Station of Remembrance, though it doesn't float in the air and is instead stationed on top of a large pillar, reminiscent of the Stations of [[Dive to the Heart]].

The {{nihongo|'''{{a|Pod Room}}'''|ポッドルーム}} is also visited in cutscene.

In ''Kingdom Hearts Birth by Sleep'', the [[Land of Departure]] is shown to be transformed into Castle Oblivion. The world appears only in cutscene, but a new room can be seen, {{nihongo|'''{{a|Room of Awakening}}'''|目覚めの部屋}} - better known as [[Chamber of Waking]] - where Ventus is left to rest. The outside of {{nihongo|'''{{a|Castle Oblivion}}'''|忘却の城}} is also briefly shown as Aqua leaves.

[[File:Terra's Guidance 01 KHBBS.png|250px|thumb|Aqua in front of Castle Oblivion.]]

Castle Oblivion was originally the [[Land of Departure]]. After the events at the [[Keyblade Graveyard]], [[Aqua]] brought a comatose [[Ventus]] to the Land of Departure, which had been destroyed in a storm of [[darkness]] by [[Master Xehanort]]. In order to keep Ventus safe, Aqua follows [[Eraqus]]'s prior instructions to seal the world's [[Keyhole]] with his [[Keyblade]] and recreate it as a labyrinth that only she could navigate, using a means devised by prior guardians. She leaves Ventus in the castle's newly-formed [[Chamber of Waking]] and promises to bring [[Terra]] back with her before waking him up. As Aqua leaves to search for Terra, she looks back on her transformed home.

The castle is eventually discovered by [[Xemnas]] of Organization XIII, who decides to convert it into a second headquarters for the Organization. It is intended to be a place to research memories, an important topic to the [[Nobody|Nobodies]] of the Organization, who have only their memories with which to form personalities. Xemnas sends [[Xigbar]] and [[Xaldin]] to recruit more members for the Organization, as they need a large group in order to run the castle. Despite rumors among the Organization that Xemnas intends to locate the Chamber of Waking, to complement the [[Chamber of Repose]] built under [[Hollow Bastion]], they never do.<ref>'''''Kingdom Hearts II Final Mix'', Xigbar:''' "But did you know there's something he DIDN'T share? The Chamber of Repose is part of a pair. The Chamber of Waking is the other. Another graveyard, if you want to call it that. It was constructed by someone other than Xemnas himself. And that's where he'll find it. That's where he'll find his other "friend.""</ref>

After defeating [[Ansem, Seeker of Darkness]], and restoring the damaged worlds, [[Sora]], [[Donald Duck]], and [[Goofy]] find themselves in a grassy field with [[King Mickey]]'s dog, [[Pluto]]. They follow Pluto along the path to Castle Oblivion, and as soon as they enter the castle, they forget all of their skills and are forced to rely upon the castle's memory-based card system. Although Marluxia and Larxene tell them their memory loss is simply the nature of the castle, it is revealed that the mysterious girl Naminé is actually the one reshaping Sora's memories, so that Marluxia can use Sora as a puppet against Xemnas. The scheme fails thanks to the meddling of Axel (who was actually on orders from Xemnas and [[Saïx]] to rid the Organization of traitors), who frees Naminé, and Marluxia and Larxene are destroyed at Sora's hand. Sora then uses one of Xemnas's pods so that Naminé can restore his memories, and is eventually moved to [[Twilight Town]].

Meanwhile, Sora's friend [[Riku]] awakens from the darkness within the lowest basement of Castle Oblivion, where he faces the remaining darkness of "Ansem". Though he initially sets out to destroy the indelible darkness in his [[heart]], with the help of [[Ansem the Wise|DiZ]], Naminé, and King Mickey, he is able to eventually embrace both the [[light]] and the dark, achieving balance. The three basement members, Vexen, Lexaeus, and Zexion seek to recruit Riku in order to counter Marluxia's use of Sora, but Riku denies their requests and vanquishes them. Riku eventually defeats the Ansem in his heart, and decides not to have Naminé seal it away completely; instead, he sets out on the "road to dawn" in order to help while Sora is sleeping.

After members of Organization XIII are sent to Castle Oblivion, [[Roxas]] learns from [[Demyx]] and Xigbar on Day 26 that someone assigned to Castle Oblivion have been annihilated.  

On Day 296, when Roxas learns from Axel that Xion was born in Castle Oblivion, he becomes determined to investigate the place for himself. The next day, Roxas was assigned to go there and hunt down [[Riku|the impostor]]. Roxas used the opportunity to investigate Castle Oblivion. Axel chose to tag along claiming that he knows the place better than anyone else in a [[black coat]]. However, barely has Roxas walked in the door when he is overcome by a strange weakness and passes out entirely, due to how close he physically was to Sora and Ventus.<ref>'''''[[Kingdom Hearts Birth by Sleep Ultimania]]''''', '''Interviewer:''' "Why did Roxas faint in Castle Oblivion on Day 297?" / '''Tetsuya Nomura:''' "Because he had gotten to close to both Sora and Ventus, his 'real self'." [https://www.khinsider.com/news/BBS-Ultimania-20-Mysteries-Solved-2546 Translation via Lissar].</ref>

Ventus continues to sleep within the Chamber of Waking, following the end of Sora and Riku's [[Mark of Mastery exam]]. Upon Sora's return to [[Traverse Town]], he smiles from Sora's happiness.

File:Marluxia (Second Form) KHUX.png|'''[[Marluxia (Second Form)]]'''<br>{{KHCoM}}

==Other appearances==

*In the manga, the monitors through which the Organization watches Sora are "Nomura-brand", a reference to [[Tetsuya Nomura]], the director of the ''{{c|Kingdom Hearts|series}}'' series.