Organization XIII

The Organization XIII characters were created by Tetsuya Nomura, director of the series, and other members of his development staff. The concept began with Xemnas as the first member and Roxas as the last. Each member's name is an anagram of their name prior to becoming a Nobody, with the letter "X" added to it. The emblem associated with the Nobodies and Organization XIII was designed to look like a splintered heart as a complement to the Heartless emblem. In terms of good and evil, Nomura tried to portray the characters ambiguously. Throughout the development of the games, Nomura has often left certain events related to and connections between the Organization XIII characters—along with the series' other characters—unexplained until the release of sequels; he feels that games should have room for fans to speculate and use their imagination.
In Chain of Memories, the staff had several of the Organization's members defeated as part of the plot. For Kingdom Hearts II, Nomura intended to allow players to fight these members again at the Coliseum. This idea, however, was dropped due to time constraints. Instead, the characters were included in Kingdom Hearts II Final Mix along with the rest of the members as data-based versions in separate optional boss fights and in a new location. Since the battles were optional, the difficulty levels of the fights was increased and the Chain of Memories-exclusive characters were given previously unseen powers. After working with the first game, Nomura gained interest in mushroom Heartless, most of which served to gain rare items in the title. This interest continued during the development of Kingdom Hearts II. He intended to add new variants in the game, but was unable to do so due to time constraints. Consequently, they are featured in the Final Mix release as the "Mushroom XIII", thirteen Heartless wearing black cloaks that also mimic traits of the Organization XIII members. For 358/2 Days, the developers believed the Organization and its large number of characters was a good fit for the intended multiplayer gameplay. Once the group was decided to be a central part of the gameplay, the staff felt Roxas's role as a member would be a suitable theme for the plot. In Kingdom Hearts: Birth by Sleep, it is revealed that the "X" that is added to their names is derived from the concept of the χ-blade, an extremely powerful Keyblade that has the ability to directly unlock Kingdom Hearts. Several members appear in Kingdom Hearts 3D: Dream Drop Distance, having regained their hearts following the destruction of their Heartless and Nobodies. However, two of the restored members joined the new Organization XIII.