Organisation XIII is a group of villains appearing in The Interference who originate from The World and are the main villains of the game Kingdom Hearts II. They are a group comprised of humanoid Nobodies, including the Nobodies of the apprentices of Ansem the Wise.
The original members of Organisation XIII were awoken, presumably on Twilight Town, after the incident at Radiant Garden. They formed a coalition group, and Xemnas chose his and the others' names by rearranging the original names and adding an X. The original members were formed of the Nobodies of Ansem's apprentices, as well as the Nobodies of Isa and Lea, two local teenagers.
While Xemnas' motive was to possess power, he informed many of the other members that the goal was to recover their hearts and, to do so, they would form an artificial Kingdom Hearts out of hearts collected through the defeat of Heartless. It was also through this lie that he attracted others to join the Organisation, with the intent to form a total of thirteen members.
Over the next ten years, the Organisation gradually collected members, until a year ago, when they came into possession of Roxas, the Nobody of Sora. During the first week of Roxas' existence, Xemnas had Vexen produce a Replica of Roxas, himself going out to recover memories from Sora during a battle, and used both the Keyblades of Roxas and the Replica, Xion, to collect hearts.
During this time, the Organisation discovered Castle Oblivion, and formed a research outpost there based on the research of memories (with Axel possessing a special mission to watch over the other members and take them out at the sign of mutiny). Because of the events of Sora's time at castle Oblivion, the treachery of Marluxia and the members under his care there became evident, and those who were not defeated by Sora or Riku were deliberately assassinated in order to preserve the Organisation, cutting the number of members down to nine members.
Meanwhile, Roxas and Xion were with the Organisation for a year, until Xion grew unstable and had Roxas destroy her. Unhappy, and with memories of Xion fading, Roxas left the Organisation, leaving seven members remaining who are seen in The Interference.
The main goal of the majority of the Organisation was originally to slay Heartless and research the effects of light and darkness on the heart, which was reflected in many of their original methods. A member scope out a new world via an extended reconnaisance mission and report back. Then, further investigations were made into the world and its inhabitants. Missions sometimes comprised of eliminating powerful Heartless, or researching into very specific areas of the world. When Roxas and Xion were in the Organisation, their missions involved reaping hearts from the Heartless to help form the artificial Kingdom Hearts. Once a mission was complete the members returned to the castle (an action given the code RTC).
Part of the Organisation was sent to Castle Oblivion, which was claimed as a research outpost. Members in this party had the overall goal of research into memories and their effects on the heart, but were given relatively free reign over their actions and methods. The actions of the Castle Oblivion group was ultimately kept classified from the other members apart from Xemnas, Xigbar and Saïx, due to the members being erased and the sole survivor's mission having been their successful elimination.
Once the Organisation have lost Roxas and Sora is active, the main Organisation's method changes drastically. There are regular meetings between the surviving Organisation members. Many of the remaining members continue their research into worlds that interest them in particular, no longer organising themselves in missions and days, but making their goal the manipulation of Sora into reaping hearts for them.
No. I, Xemnas: Superior of the In-BetweenEdit
The leader of the Nobodies and the oldest known humanoid Nobody, Xemnas commands the group and makes all of the executive decisions. He possesses enormous amounts of power, physically (being the hardiest Nobody known to exist), magically (able to form different armours, change the battle field, and manipulate The World That Never Was' architecture) and officially (having command over all types of Nobodies, having executive command over all actions of the Organisation, both research-related and conquest-related). Xemnas wields twin laser swords and commands the element of Nothingness. He is the only Organisation member with command over Sorceror Nobodies.
He is the last of the Nobodies to be defeated, and initially challenges Alex solo. Then, after the battle, he attempts to utilise the power of his false Kingdom Hearts. He goes through multiple incarnations before he is finally defeated in the 'Realm of Nothingness' by Sora, Alex and Riku.
No. II, Xigbar: FreeshooterEdit
Xigbar is Xemnas' second-in-command and, outside of Sora and Alex's view, quite possibly one of his closest allies as well, having personal access to many of his plans and and the plans of his predecessors. Perhaps due to his exclusive access, he is extremely laid back and casual, barely reacting seriously to tragedies within the Organisation. He commands a pair of large arrowguns which he can control to form a sniper rifle, and is capable of teleporting short distances without using Dark Corridors. Xigbar commands the element of Space, and is represented by Sniper Nobodies.
Xigbar taunts the party at various locations, and is eventually faced down at The World That Never Was, by Sora, Lea, Donald and Goofy. After the battle, Xigbar vanishes, thought to be dead. In reality, he escapes the battle, and alters his headstone in the Proof of Existence.
No. III, Xaldin: Whirlwind LancerEdit
Xaldin investigates Beast's Castle during The Interference, and takes interest in manipulating the heart of Beast, trying to force him to submit to the darkness via psychological warfare. His motive is to turn the Beast into a powerful Heartless that can be weaponised, and doesn't understand the concept of love, believing that the only thing really important to the Beast is the rose and the curse on his body. He wields lances and commands the element of Wind, and commands Dragoon Nobodies.
Sora and Alex eventually defeat him at Beast's Castle with the help of King Mickey, referencing the ability to play as Mickey if Sora receives a game over on this battle.
No. VII, Saïx: Luna DivinerEdit
Saïx is Xemnas' next in command after Xigbar, acting as his assistant. He is Xemnas' greatest defender and extremely allied to the Organisation's cause, unlike the other members who show at least some deviation from rules or regulations, and was the middleman between Xemnas and the others, delivering the day's missions to each one. When enraged or powered up, Saïx uses his abilities to go berserk. Saïx wields a giant claymore sword and commands the element of Moon, and commands Berserker Nobodies.
He is initially assigned to Alex's case and tries to lure him into the Organisation, personally not considering him much of a threat. After Alex turns him down, he occasionally talks with Sora and at one point directly challenges Maleficent's authority. Alex and King Mickey defeat him together at The World That Never Was.
No. VIII, Axel: Flurry of Dancing FlamesEdit
Axel, alongside Saix, is one of the only members of the Organisation to have been around since the beginning, but not be an assistant. Having been He has been assisting Sora ever since Castle Oblivion, and was a good friend of Roxas's. Axel wields a pair of chakram and commands the element of Fire, and at one point commanded Assassin Nobodies.
By the time of The Interference, Axel is already showing distrust to the Organisation, and begins acting out of line, first trying to rescue Roxas out of desperation (eventually fighting him when disappointed that he doesn't truly recognise him), and then sneaking around to help Sora. Eventually, when he comes to help Sora access The World That Never Was, Alex stops Axel from using a suicide attack on a swarm of Nobodies, and he receives his original heart after the artificial Kingdom Hearts is destroyed, becoming Lea, at which point he returns to Radiant Garden as an adult.
No. IX, Demyx: Melodious NocturneEdit
Demyx is technically investigating Olympus Coliseum, and the effects of items such as the Olympus, although he was probably originally there to make deals with Hades. Unfortunately, Demyx is extremely cowardly and hates working, prefering to stay away and on the sidelines, or playing his music. However, he turns deadly serious when it is implied that he has no feelings. Demyx can create water clones to do his bidding. He wields a large sitar and commands the element of Water, as well as holding command over Dancer Nobodies.
Demyx is briefly met during the first Olympus Coliseum visit, but only performs a single boss battle. He is eventually defeated during the assault on Radiant Garden by Sora, Alex, Kairi, Donald and Goofy.
No. X, Luxord: Gambler of FateEdit
Luxord investigates Port Royal, taking interest in the cursed Aztec gold that dwells on the Isla de Muerta. He is obsessed with gambling and games of chance, basing much of his languages and beliefs around them. He wields a large set of transforming cards, and has the ability to transform enemies into cards or dice by playing games with them. He commands the element of Time, as well as Gambler Nobodies.
Sora, Donald and Goofy are presumed to defeat Luxord while Alex and Mickey walk with Ansem the Wise.
During The Interference, Roxas starts off trapped inside the Virtual Twilight Town, and eventually is reunited with Sora, although not entirely by choice. He starts acting out through Sora, and eventually makes contact with Joumae. After a battle with Sora and Alex, Roxas is able to speak his mind at any point. Roxas once wielded a Keyblade and commanded the element of Light. He may have at one point had control over Samurai Nobodies, and used to fight them in certain missions.
All of the members below were killed prior to the events of Kingdom Hearts II and so do not appear in The Interference.
No. IV, Vexen: Chilly AcademicEdit
A Nobody of one of Ansem's apprentices, Vexen was the Organisation's major researcher and scientist. As well as performing some cursory investigation of worlds, Vexen was usually charged with the investigation of more philosophical matters of the heart, and was the member of the Organisation who created Replicas. He was sent to the research outpost at Castle Oblivion to perform research on Naminé and her memory manipulation powers, and was killed by Axel when he tried to reveal Roxas' existence to Sora. He wielded a large shield and commanded the element of Ice.
No. V, Lexaeus: Silent HeroEdit
A Nobody of a Radiant Garden castle guard and apprentice of Ansem, Lexaeus was one of the Organisation's original members and a member sent to the outpost at Castle Oblivion to intercept Sora and Riku, though he only ever came into contact with Riku, who defeated him. Of his personality, it is known that he was only loyal to Zexion. He wielded a heavy blade referred to as an Axe Sword and was the Organisation's strongest member physically. He commanded the element of Earth.
No. VI, Zexion: Cloaked SchemerEdit
The Nobody of a boy who was taken in by Ansem, Zexion was the last of the Organisation's original members, and the master of Castle Oblivion's basement floors. He was extremly studious and perceptive, and possessed a keen sense of smell, with the ability to detect not only darkness in a space, but specific types of darkness and individuals. He antagonised Riku during his trip into the castle, but was eventually defeated after trying to trick him. Zexion wielded a Lexicon which he used to mimic the attacks and abilities of his foes. He commanded the element of Illusion.
No. XI, Marluxia: Graceful AssassinEdit
One of the most recent acquisitions in the Organisation, Marluxia was assigned as the master of Castle Oblivion's floors. While there, he attempted to mastermind a rebellion against the Organisation members at headquarters, and planned to use Naminé's memory abilities to enslave Sora and overthrow the Superior. Unfortunately for him, his fellow members were killed off, many betraying him, and Sora defeated him finally. Marluxia wielded a large scythe when he was alive, which he had the ability to summon from a single flower petal. He commanded the element of Flower and had control over a large, powerful Nobody which he utilised in his final battle with Sora.
No. XII, Larxene: Savage NymphEdit
Another recent acquisition by the Organisation, Larxene was one of the members sent to Castle Oblivion. She was loyal to her direct superior Marluxia and joined him in his plans to commit treachery against the rest of Organisation XIII, but was defeated by Sora. Larxene was in posession of a set of throwing knives, but often just slapped people in her way first, and was notably sadistic. She commanded the element of Lightning.
No. XIV, XionEdit
Xion was a Replica created by Vexen to act as the Organisation's potential replacement for Sora and Roxas. She was to do this via absorbing memories of Roxas, which affected her appearance, and was ultimately reprogrammed to try and absorb Roxas directly when she showed regret and rebellion against her task. Upon her death, because she was comprised of memories, everybody who came into contact with her forgot about her. Xion wielded a copy of Roxas' Keyblade and used his element of Light.