Real Organization XIII

The real Organization XIII (真のXIII機関), also known as the thirteen seekers of darkness (13人の闇の探求者), is a group consisting of thirteen different incarnations of Master Xehanort that debuts in Kingdom Hearts 3D: Dream Drop Distance. It was first mentioned by Yen Sid in Signs of What's Next when he claims that one Keyblade Master will not be enough to counter what is "not a single one of Xehanort".

Between Kingdom Hearts Birth by Sleep and Kingdom Hearts
The true purpose of the original Organization XIII led by Xemnas was for each of the Nobody members to host a fragment of Master Xehanort's heart, turning them into clones of Xehanort, but the members' unforeseen independence made this goal impossible to realize.

However, in anticipation of this failure, Master Xehanort had arranged to send Ansem, Seeker of Darkness back in time to his youth, to meet Young Xehanort and become a portal, travelling to different periods of time and gathering different incarnations of Xehanort who would be added to the ranks of a new Organization.

Kingdom Hearts 3D: Dream Drop Distance
Young Xehanort succeeds in filling twelve of the Organization's seats, and he and the revived Master Xehanort attempt to make Sora into the final vessel. When Sora is rescued by Riku, Mickey, and company, the Organization disperses to their proper times, while Master Xehanort remains confident that in time he will complete his Organization.

Main members

 * Master Xehanort: The original Xehanort and the mastermind behind all of his incarnations' actions.
 * Young Xehanort: Master Xehanort in his youth, who traveled through time with the assistance of Ansem; his heart is brought from the past and placed within a Replica.
 * Terra-Xehanort: A version of Master Xehanort from when he possessed Terra; his heart is brought from the past and placed within Terra's recompleted body.
 * Ansem, Seeker of Darkness: Terra-Xehanort's Heartless; his heart is brought from the past and placed within a Replica.
 * Xemnas: Terra-Xehanort's Nobody and the leader of the original Organization XIII; his heart is brought from the past and placed within a Replica.
 * Vanitas: The embodiment of Ventus's darkness who seeks to extract Ventus's heart from Sora; his heart is brought from the past and placed within a Replica.
 * Xigbar: Braig's Nobody and a member of the original Organization XIII, and actually Luxu in disguise.
 * Saïx: Isa's Nobody and a member of the original Organization XIII.
 * Luxord: A Nobody and a member of the original Organization XIII.
 * Marluxia: Lauriam's Nobody and a member of the original Organization XIII.
 * Larxene: Elrena's Nobody and a member of the original Organization XIII.
 * Dark Riku: The Replica of Riku from his early time as a brainwashed puppet; his heart is brought from the past and placed within a Replica.
 * Xion: The Replica of Sora from her early days in the original Organization XIII; her heart is brought from the past and placed within a Replica. When her true heart, within Sora, is sparked by emotion, she is recompleted and defects to the Seven Guardians of Light.

Reserve members

 * Vexen: Even's Nobody and a member of the original Organization XIII. Brought back only as a reserve member, mainly to continue the Replica Program.
 * Demyx: A Nobody and a member of the original Organization XIII. His place was taken by Dark Riku.

Other members

 * Replica Xehanorts: Replicas of Xehanort who assist him in Scala ad Caelum.

Echte Organisation XIII