Xemnas, Xehanort's Nobody, in the Kingdom Hearts series. Xemnas first appears as a secret boss at Hollow Bastion in Kingdom Hearts Final Mix. Kingdom Hearts II introduces that Nobodies are born when a Heartless is created, and reveals that the Nobody of Ansem is "Unknown" and the "Superior" of Organization XIII, Xemnas. Mickey Mouse, who had met Ansem before the story of Kingdom Hearts, reveals that the Ansem that Sora encountered was actually the Heartless of Xehanort, one of Ansem the Wise's students. "Secret Ansem Reports", written by Ansem the Wise, are found throughout the game, and explain that Xehanort was a castaway turned apprentice and subject who lost his memories and that he took Ansem's name, created the Heartless, and split his being into two, creating the sapient Heartless and Xemnas. Five other apprentices participated in the experiments, and their Nobodies formed the Organization with Xemnas.
Organization XIII members explain that Xemnas seeks to increase Kingdom Hearts' power by having Sora defeat Heartless, releasing the hearts trapped within them, which flock back to Kingdom Hearts. Xemnas desires to create a "brand new world, one heart at a time."At Organization XIII's base, DiZ reveals himself to be Ansem the Wise, and uses a machine to take Kingdom Hearts' energy. This causes many hearts from Kingdom Hearts to fall out, removing much potential. Regardless, Xemnas takes what is left of Kingdom Hearts' power and battles Sora in multiple forms, eventually defeated and "fading to darkness". Kingdom Hearts II Ultimania describes Xemnas as using the power of nothingness and red energy blades called Aerial Blades in battle; and controlling Sorcerer Nobodies, a lesser type of Nobody.
Kingdom Hearts II Final Mix
Kingdom Hearts II Final Mix added new cutscenes that expanded on the Organization and Xemnas. Xemnas is often seen in meetings between the Organization members, presiding over them. Xemnas, in a flashback sequence, is seen walking into the depths of the laboratory at the Radiant Garden to enter at the "Chamber of Sleep" speak to armor that belongs to a female knight with a Keyblade, referring to it as a friend. Xigbar, a member of the Organization, explains that after people with Keyblades fought and left, Xehanort was found by Ansem the Wise.