Castle Oblivion
Castle Oblivion (忘却の城, Bōkyaku no Shiro?) is a mysterious fortress featured in Kingdom Hearts: Chain of Memories and serves as the main setting of the game. The castle is decorated with a rose motif and has twenty five levels; thirteen floors and twelve basements. The lord of the castle is Marluxia, a member of Organization XIII.[48] This castle is one of the few worlds known to be found in neither the realm of light or the realm of darkness, but is instead found on a plane somewhere in between the two realms. In the balance between light and darkness within this in-between realm, however, Castle Oblivion is more closely tied to the realm of darkness than the realm of light.[13]
Castle Oblivion is dominated by the use of cards. When entering the castle, one's memories and abilities are quantified into cards. Castle Oblivion's floors can be transmuted into different forms and layouts through the use of "world cards" derived from one's memories, as well as "map cards" which determine the properties of individual rooms. World cards based on Traverse Town, Wonderland, Olympus Coliseum, Agrabah, Halloween Town, Monstro, Atlantica, Never Land, Hollow Bastion, 100 Acre Wood, Twilight Town, and Destiny Islands have been created from Sora and sora's memories.[49]