A Nobody (ノーバディ, Nōbadi?) is the body and soul of a strong-willed individual who has lost their heart. While this enemy type makes its first appearance in Kingdom Hearts II, members of Organization XIII appeared in Kingdom Hearts Final Mix and Kingdom Hearts Chain of Memories, albeit as unclassified opponents.
The Nobody emblem is a splintered, upside-down heart that resembles Terra's Mark as Xemnas remembers it. It appears for the first time in Kingdom Hearts Chain of Memories, in which it is emblazoned on the Specter's head and designates sleights used by the Riku Replica and members of Organization XIII.
Between Kingdom Hearts Birth by Sleep and Kingdom Hearts
Needing vessels for his plan to create thirteen darknesses, Xehanort tricks Aeleus, Dilan, Even and Ienzo into giving up their hearts as part of their research into the nature of the heart and the Heartless, using his Keyblade to extract their hearts. When Braig questions his intentions, Xehanort simply extracts his heart next. Following this, he turns the Keyblade on himself and extracts his own heart. This creates the first six members of Organization XIII, who are commanded by Xemnas, Xehanort's Nobody, to recruit more members into their ranks.
Sora becomes a Heartless in Hollow Bastion. This creates two Nobodies: Roxas and Naminé. The former appears in Twilight Town and joins Organization XIII, while the latter finds herself in Castle Oblivion and in Organization XIII's custody.
On a return trip to Hollow Bastion, Sora battles and defeats Xemnas.
Kingdom Hearts Chain of Memories
Marluxia, the Organization's Number XI, leads Sora and his friends to Castle Oblivion. There, he forces Naminé to tamper with Sora's memories in an attempt to gain the Keyblade's power. When Riku awakens in Castle Oblivion's lower levels, he faces some of the Organization's founding members and learns Nobodies belong to neither the light nor darkness.
Kingdom Hearts 358/2 Days
Organization XIII uses Roxas and Xion to collect hearts. This is in accordance with its plan to create Kingdom Hearts, which will enable its members to become whole again. The Organization also searches for the Chamber of Waking and develops the Replica Program.
Roxas, who discusses being a Nobody with his friend Axel, battles Dusks and Samurais in a series of three trials at The World That Never Was: Mission 10, Mission 33, and Mission 71. He confronts more when he attempts to abandon Organization XIII.
Kingdom Hearts II
After Roxas is placed in a simulated Twilight Town, Axel is ordered to retrieve him. The Organization's Number VIII teams up with several lesser Nobodies in an attempt to get his friend back.
Sora, Donald, and Goofy learn about Nobodies from Yen Sid at the Mysterious Tower. They clash with these foes multiple times, and they destroy the surviving members of Organization XIII: Xemnas, Xigbar, Xaldin, Saïx, Demyx, and Luxord.
Kingdom Hearts 3D: Dream Drop Distance
In The World That Never Was, a resurrected Xemnas tells Sora that Nobodies can grow new hearts and feel emotions. It is revealed this fact was deliberately kept from the other members of Organization XIII, who were meant to inherit Master Xehanort's heart through Kingdom Hearts.
Ienzo reveals to Lea that when a Heartless and Nobody are destroyed and their hearts find their vessels, they are returned to the place they became a Heartless and Nobody. However, if that world is unavailable or otherwise destroyed, they would appear in Traverse Town.
Kingdom Hearts III
Xigbar, Saïx, Vexen, Demyx, Luxord, Marluxia and Larxene return to Nobodies to become members of the real Organization XIII; Xemnas's heart is extracted from the past and placed in a replica, so he may also serve as a member. Xigbar, Luxord, Marluxia, and Larxene encounter Sora throughout the worlds on their respective missions to find and protect the New Seven Hearts and to find the Black Box. Two new breeds of lesser Nobody, Reaper and Ninja are also introduced as adversaries.
At the Keyblade Graveyard, swarms of Nobodies are called in by Xemnas to help the Heartless and Unversed wear down the Seven Guardians of Light. After Terra-Xehanort is repelled by the Lingering Will, another wave of Nobodies is summoned by Dark Riku and Xigbar along with more Heartless. Thanks to the combined efforts of the traitorous Vexen and Demyx, along with Ansem the Wise, Roxas is revived using a replica body. Luxord, Marluxia, and Larxene are defeated, beginning their re-completion again.
Lesser Nobodies are humanoid enemies that are primarily grey in coloration. They possess a certain elasticity that enables them to contort their bodies into a variety of shapes. An often overlooked feature of lesser Nobodies is their lack of eyes; though some such as the Dragoon and Samurai emulate eyes. This means Nobodies are blind and rely on their other senses. Lesser Nobodies bear the Nobody emblem. In Kingdom Hearts III, Nobodies have a metallic sheen.
Gummi Nobodies come in a variety of colors and have streamlined, machine-like bodies. Like lesser Nobodies, they also bear the Nobody emblem.
The members of Organization XIII, Nobodies who possess the strongest of wills, retain their human forms. Their bodies lack the Nobody emblem, which instead influences the look of their weapons; primarily this results in their weapons having extra spikes. There are exceptions, such as Book of Retribution and Skysplitter have the spikes as pictures or engraving.
Unlike their Heartless counterparts, the Nobodies are not classified by method of creation, but instead by rank. High-ranking Nobodies generally serve a specific Organization member, while low-ranking Nobodies are used by all members. Another distinct difference is that Nobodies are all naturally born, unlike the Heartlless who have the artificially-created Emblem variety; thus this makes the Nobody emblem a natural feature on lesser Nobodies.
Nobodies are created when strong-willed individuals lose their hearts and fall to darkness. The bodies that remain give Nobodies their form, while the abandoned souls give them life. People with the strongest wills are able to retain human form when they become Nobodies. Despite being formed by the discarded body, it appears that Nobodies are primarily defined by the heart that leaves said body; Naminé is considered the Nobody of Kairi due to being the result of Kairi’s heart leaving Sora’s body when he became a Heartless, and Xemnas is made of Terra’s body and soul, but is more strongly tied to Xehanort due to Master Xehanort’s heart having left when Terra-Xehanort gave in to darkness.
Nobodies are said to be incapable of experiencing emotion. While they tend to retain the memories they made as humans, the feelings they display are merely an act. Memories alone enable Nobodies to correctly respond to the situations in which they find themselves. Despite this, Nobodies are able to think for themselves and are organized, whereas the Heartless are more instinctual enemies, generally attacking opponents in massive swarms, relying on sheer strength of numbers to defeat them. Nobodies feel physical pain, and in the Kingdom Hearts Chain of Memories manga, they are seen reading, cooking, or doing jigsaw puzzles in an attempt to fill their emptiness. Innate behaviors and preferences are retained, such as Axel's fondness for sea-salt ice cream and Vexen's obsession with research. Humanoid Nobodies can still age, as shown with Zexion, who became a Nobody as a child, and Naminé.
It is possible for Nobodies to grow new hearts. Master Xehanort and Xemnas use this to their advantage, and Sora learns this when he experiences Roxas's pain first-hand at the end of his hijacked Mark of Mastery exam. In Sora's words, one must "have a heart to cry."  Should Nobodies without memories like Roxas and Naminé regrow hearts, they become entirely new people from their original selves.
When defeated, Nobodies fade back into darkness. Their defeat, in combination with the destruction of their original selves' Heartless, restores their human forms. Completed once more, the Nobodies' memories remain intact. However, their human form will still have to deal with any trauma resulting from the attack that destroyed their physical body.[?]In Sora's case, whose Nobody gained a heart of its own, he does not retain any memory from their Nobody consciously. Because of such, a running gag is that those who knew Roxas in the first Organization mistakenly believe that Sora retains memory of Roxas's time with them. This led to the members of the original Organization XIII repeatedly calling Sora "Roxas", much to his annoyance and confusion.
High-ranking Nobodies can be reduced to a lower rank. Members of Organization XIII consider being turned into a Dusk a form of discipline.
Replicas (レプリカ, Repurika?) are artificial copies of people. Created by Organization XIII, the initial batch are a special type of Nobody. They first appear in Kingdom Hearts Chain of Memories.
Replicas are blank figures, akin to mannequins; they take the form of whatever heart or data of a heart is placed inside of it. They have the same skills as the individuals used to create them. They also have the unique ability to absorb other individuals. The Riku Replica was created using data Vexen collected from fighting Riku, while Xemnas used Sora's memories to make Xion, an imperfect replica of Roxas. In the manga, Vexen fashioned 44 replicas of himself.
Over time replicas like the Riku Replica and Xion formed identities, and therefore "hearts", of their own, becoming their own people.
List of Nobodies
Notes and references