Nobody (ノーバディ, Nōbadi) is what is left behind by those whose hearts have been consumed by Heartless. The first generic Nobodies are seen in Kingdom Hearts II, although Xemnas appeared as early as Kingdom Hearts, it was unknown that he was a Nobody. They are made of body and soul.
Between Kingdom Hearts Birth by Sleep and Kingdom Hearts 358/2 DaysEdit
Terra-Xehanort's experiments culminated in his fellow apprentices' hearts and the creation of his own Heartless, Ansem, Seeker of Darkness, and Nobody, Xemnas. Together with Xigbar, the Nobody of Master Xehanort's co-conspirator, Braig, Xemnas founded Organization XIII, recruiting the Nobodies of the remaining apprentices as founding members. They recruited additional members and took command over the lesser Nobodies.
When Sora becomes a Heartless in Hollow Bastion while freeing Kairi's heart from his body, two Nobodies are born: Roxas appears in Twilight Town, where he is recruited by Xemnas as the thirteenth Organization member, while Naminé is born in Castle Oblivion, which the Organization has taken as a secondary base, and she is taken into Organization custody.
During his second trip to Hollow Bastion, Sora encounters Xemnas in the room where Maleficent was defeated in her dragon form, and they fight before Xemnas disappears.
Kingdom Hearts: Chain of MemoriesEdit
Sora is coaxed into entering Castle Oblivion by Marluxia, who attempts to manipulate Sora using Naminé's power over his memory. He and Larxene tell Naminé that if she inserts herself in Sora's memory, she can be "somebody" instead of just a Nobody.
Riku, who emerges from the Realm of Darkness in the basement of Castle Oblivion, encounters several Organization members, learning a bit about their nature as Nobodies along the way.
The members of the Organization stationed in Castle Oblivion don't use the services of lesser Nobodies against Sora or Riku, choosing to fight for themselves when not relying on the Heartless inhabiting the castle.
Kingdom Hearts 358/2 DaysEdit
The Organization members are not accompanied by lesser Nobodies during missions. However, Roxas faces Dusks and Samurais during three skill trials at The World That Never Was. More Dusks and Samurais attempt to stop Roxas when he finally leaves the Organization.
Kingdom Hearts IIEdit
Sora, Donald, and Goofy encounter a group of Nobodies in front of the Twilight Town train station, but don't know what they are. When they meet Yen Sidat the Mysterious Tower, he explains the nature of Nobodies and Organization XIII while telling them of their new mission. He shows them images of Dusks and hooded Organization members. Sora clashes with the Nobodies multiple times, including the remaining members Demyx, Xaldin, Xigbar, Luxord, Saïx, and Xemnas.
Kingdom Hearts 3D: Dream Drop DistanceEdit
Within the Sleeping Worlds, Xemnas reveals to Sora that Nobodies actually can cultivate new hearts within their bodies and develop emotions on their own, as was the case with Roxas, Axel, and Naminé, but this fact was deliberately kept from the other Organization members as part of Master Xehanort's plans to use them as vessels for his heart.