Castle Oblivion is the dominion of Toxin and Nexko, although he has been known to share it with Thraxganb from time to time because of perceived similarities. Marluxia also resides in the Castle, though his is granted this privelege by Xolduc for (seemingly) being more trustworthy and competent than Xemnas.
It also holds a doorway to an alternate universe.
|The Jack of Spades | Kurochi|
|The Midnight Syndicate|
|Xolduc | Nexko | Telmuci'ixa | Xemnas | Zexion | Saïx | Marluxia | Noxel | Roxian | Zolgbex | Xertra | Juxak | Thraxganb | Toxin|
|Cole MacGrath | Alex Mercer | Clare | Kazuki Muto | Thor | Xashowd | Xion|
|Traitors to the Syndicate|
|Zexion | Marluxia | Roxian | Zolgbex | Xertra | Thraxganb|
|Kurochi | The Jack of Spades | The Lingering Sentiment|
|Metropolia | Grand Tempest | Voracious Torrent | Twilight Town | Castle Oblivion|