Zexion

Kingdom Hearts 358/2 Days
Zexion appeared in Chain of Memories as a participant in the struggle within the Organization between the newer and veteran members. He is also central to the plot to use Riku as a puppet in Castle Oblivion. Zexion appears in the upcoming game Kingdom Hearts 358/2 Days, as one of the playable characters in multiplayer mode. Tetsuya Nomura called Zexion a "mysterious character" for the game.

Kingdom Hearts 358/2 Days
In 358/2 Days, Zexion is present when Xion joins Organization XIII. Zexion later teaches Roxas how to fill the mission gauge in Twilight Town before being sent away to Castle Oblivion. True to his personality, he was patient with the Keyblade wielder, carefully and calmly explaining the filling of the gauge in great detail.

Zexion also makes a cameo appearance later in the storyline. During Xion's nightmare on Destiny Islands, Roxas stands on the beach of the island, missing his friend. He later sees the hooded Sora copy and approaches her. She removes her hood and turns out to be none other than Zexion, who proceeds to taunt a younger version of Riku as he did in Kingdom Hearts: Chain of Memories. The scene then begins to fade, Xion (in the form of the shocked Roxas) undergoing a series of transformations until she finally takes Sora's form for the first time.

Discovering Riku
After Sora had been lured into Castle Oblivion, Zexion discovers two other scents deep in the dungeons of the castle. One of them belongs to a Maleficent formed from someone's memory, having been given life by Castle Oblivion's unique properties. Originally, he mistakes the other scent to be that of "The Superior". Eventually, however, Zexion and his cohorts determine that the scent belongs to Riku, who had appeared in the Castle by force of will after Sora's arrival. Vexen hypothesizes that the darkness in Riku's heart ("Ansem") caused Zexion to mistake him for "the Superior", calling the effect "fascinating". Specifically, Riku's heart is plagued by the presence of Ansem.

Opposition to Marluxia
Zexion, as well as Lexaeus and Vexen, come to see that Marluxia, keeper of Castle Oblivion, intends to take control of Organization XIII, with the help of Larxene, by using Sora as their puppet. Though they see that they can use Riku to counter Sora, they decide to oppose Marluxia's plot by having Vexen investigate Marluxia under the guise of offering to help using the Riku Replica he creates with combat data from the real Riku. However, Vexen is eventually killed on Marluxia's orders by Axel, whom Zexion and Lexaeus had been unsure about trusting. Axel later tells them he had performed the deed only to gain Marluxia's trust, and continues to cooperate with Zexion in tracking Sora and Riku.

Seeing that Vexen's efforts to derail Marluxia's plan had failed, Zexion sends Lexaeus to sway Riku into joining them, but Riku refuses to allow darkness to control him and defeats Lexaeus in combat. With the last of his strength, Lexaeus manages to knock Riku unconscious, rendering him helpless. However, before he can finish the job, Xehanort's Heartless takes control of Riku's body and finishes Lexaeus with the power of darkness. Riku is then enveloped in his own personal darkness, where "Ansem" tries to corrupt him - however, he is saved by King Mickey and continues ascending Castle Oblivion.

Confronting Riku
After Lexaeus dies in his failed attempt to subvert Riku's resistance to darkness, Zexion discusses the Organization's fate with Axel and learns that Larxene has been killed as well, bringing the number of Organization members eliminated to three. Axel tells him that he himself was defeated by Sora as well, and that Marluxia is almost certainly the next to go. Zexion decides that with the possibility of Marluxia dying soon, Riku is no longer needed, and heads off to intercept him.

Zexion appears before Riku while he is between floors of the castle, shortly after the death of Marluxia. As the force of Marluxia's death shakes the castle, Riku halts with surprise and comments how a very strong scent in the air has died. Zexion materializes in front of him and tells him that Sora has just defeated Marluxia. Riku is surprised to learn that Sora is also in the castle, but Zexion tells him he would never be able to face him after having such darkness in his heart.

He gives Riku a World Card to Destiny Islands, and Riku winds up facing a Darkside Heartless. After he defeats it, Zexion reappears, and continues to play on his guilt, telling him Sora will always oppose him as a host of the dark. Sora then appears himself, brandishing his Keyblade and accusing Riku of being corrupt. He envelops Riku in light, rendering him unable to do anything. Instead of drowning Riku into helplessness, however, the predicament causes Naminé to come to his aid, in the guise of Kairi, telling him that he should stop rejecting the darkness within his heart, and instead tells him to draw on that power to free himself of the oppressing light and strike out at Sora. He wounds Sora, whose disguise falters to reveal Zexion, who had been using his powers of illusion to deceive Riku. Zexion is astounded by Riku's ability to control the darkness, and is also enraged at his perseverance. He decides to engage Riku in combat himself, albeit wounded, but still puts up a rather difficult fight. However, Riku eventually overcomes and defeats Zexion.After escaping from Riku, Zexion appears in a room, where Axel and a companion are waiting. In a panic, Zexion thinks Axel's companion is Riku himself, but then realizes it's only Riku Replica. Axel and the replica then approach Zexion, and Axel directs the replica's attention to his lack of wholeness. He tells him that if he can find strength that the real Riku doesn't have, he can become a whole person of his own, rather than a mere puppet or whole copy of Riku. Axel then suggests that he should start by eliminating Zexion. Zexion is horrified by Axel's suggestion, but before he can do anything, the replica kills Zexion and takes his power; judging by Axel's line of Zexion finding out "way too much", it can be assumed that Axel purposely set this up to keep Zexion quiet about what had transpired at the castle. Zexion's death scene is different between versions. In the GBA original, the screen fades to black, and all that is heard is a clashing of blades while Zexion screams, "NOOOOO!!". In Re:Chain of Memories, the Riku Replica grabs Zexion by the collar and sucks out his life force, causing him to fade back into darkness.

Kingdom Hearts: Chain of Memories Manga
In the manga adaption of Kingdom Hearts: Chain of Memories, Zexion does not escape from Riku after being defeated in battle on the virtual Destiny Islands. Instead, Zexion appears to Riku and taunts him about being weaker than Sora because he rejects the Darkness. He transforms into Sora and rebukes him for embracing it, tricking Riku into thinking it is actually Sora accusing him instead of Zexion. Later, after changing back into himself, he further influences him by saying Sora would never want to see him again because he ran away from the light, but the Organization would welcome him with open arms. He consumes Riku in light, making him unable to do anything and attempts to show the pain of the light, but Riku, enraged, instead turns on Zexion and kills him with a slash of his Soul Eater. Zexion never fights with Riku Replica.

In the manga, Zexion visits the floor where Lexaeus was killed, and he never makes an alliance with Axel.

Personality
Zexion is sometimes seen smirking or grinning, something he and Larxene share. Unlike the other members, he conducts his tasks in a veil of secrecy, suggesting a darker sort of persona. Zexion apparently also holds a fondness for literature and the humanities, which is noticed in the weapons he utilizes and his manner of speech when speaking to other members. It was most notable in 358/2 Days when he had assisted Roxas in his tutorial mission, throughly explaining details in a polite fashion. (Another instance of this is the name of one of his Lexicons, the 'Heretic's Memorandum'.) His approach to dealing with his enemies; namely, he does not fight them outright, but uses schemes and illusions to bring them down. He wields the element of "illusion" but originally did not show his weapon in Kingdom Hearts: Chain of Memories. His weapon panel in the Proof of Existence (an area of the Castle that Never Was displaying the Organization members' weapons and titles) is shattered in Kingdom Hearts II, but it is revealed in Kingdom Hearts Re:Chain of Memories that his weapon is, in fact, a lexicon, which attacks through a flurry of pages and trapping people within it. Like Riku, Zexion has the ability to identify the "scents" of others, with great accuracy and at great distances. The "scent" he smells may be based off other things than mere odor, and is affected by presence of darkness in the heart, an entity's power in the castle, and other factors.

Zexion stands out in Kingdom Hearts: Chain of Memories as the mastermind behind the actions of those members who are actually loyal to the Organization. He is aware of the Organization's decline, calling it "deplorable". Zexion also takes his missions seriously (In contrast to Demyx or Xigbar, who do not take their missions seriously.)

Of the three senior members (the other two being Lexaeus and Vexen) with the lowest thrones in their meeting chamber, named "Where Nothing Gathers", he seems to have the highest, while Vexen's is the lowest, indicating he is the most competent of the three. That is certainly not untrue, as he is the mastermind for the plot chronicled in the Reverse/Rebirth storyline, which only failed through Axel's betrayal of both sides; Axel's betrayal of Marluxia, by releasing Naminé, caused a chain reaction, as it was Naminé, in the guise of Kairi, who assisted Riku in breaking free of Zexion's trap in the Destiny Islands, which caught Zexion off-guard. Immediately after, Axel himself appeared and had the Riku Replica kill Zexion.

The fact that he acts as the mastermind behind Lexaeus and Vexen shows that his rank in the organization may in fact be higher than his number would lead one to believe. This is further reinforced by an additional scene in Kingdom Hearts II Final Mix where he is seen to have a conversation with Xigbar. He reprimands Xigbar's habit of eavesdropping, and even talks down to him, stating that he should get back to work. When Xigbar informs him that he was hoping to just have a "friendly chat" with him, Zexion tells him he has more work to attend to, and finishes the conversation by telling Xigbar that if he is through working, then it would be in his best interest to get rest.

It is speculated that Xemnas may have known about the rebellious thoughts harbored by Marluxia, and as a result placed Zexion in command of the lower regions of Castle Oblivion in order to weed out the traitor. This would seem plausible based on Zexion's apparent rank and level of competence, though nothing official has been stated in regards to it.

Zexion to some appears to be emotionally distant and anti-social, but this is not completely true. This is observed in his death. Upon Axel's dialogue with the Riku replica, Zexion's horrified reaction shows that he clearly does not want to die. He has an undying sense of duty to the Organization, which is certainly not untrue as he is the most competent of the basement members and goes to any length to ensure the success of his missions. At times, he can also be humorous and jest with other members when the moment shows itself. A good example of this is in Re:Chain of Memories where it's shown that he and Axel are having a friendly gamble at which Organization member in the castle will be the next to die (something they've been apparently doing ever since Vexen got killed by Axel). Axel proves to win that particular round when he accurately predicts that Marluxia will be the next to die.

Fighting Style
Initially, Zexion was never seen in combat, and his weapon and elemental attribute were a mystery. In an effort to keep Zexion's weapon unknown, his gravestone in the The World That Never Was laid destroyed, as all the gravestones depicted the member's weapon of choice. Re: Chain of Memories and Kingdom Hearts II: Final Mix revealed his weapon as the Lexicon. Zexion can use his Lexicon to mimic the attacks of his enemies in 358/2 Days and in Re: Chain of Memories. This ability follows a trend where the Organization members bear abilities and skills mirroring those of Final Fantasy jobs (ex. Xaldin = Dragoon, Luxord = Gambler, etc.). In Zexion's case, his abilities mirror those of a Blue Mage, who can learn and mimic enemy attacks.

In Kingdom Hearts Re:Chain of Memories, he has a unique fighting style; he steals and hoards his foe's cards until he has enough to use it in his own deck. He has copies of his lexicon float around and attack the opponent. His standard attack steals Riku's attack cards, and his standard sleight creates a tornado of dark energy that drags Riku in, and then damages him while stealing his cards. When Zexion hoards enough cards, he copies the Soul Eater and clones himself, gaining the uses of two new sleights. In one, Zexion's clones vanish while Zexion grabs Riku and drains his HP. Zexion's other new sleight is a sleight in which he and his clones vanish and then reappear near the perimeter of the island and each fire an energy beam. The beams meet and slowly forms a ball of energy as Zexion and his clones rotate around the island before the energy ball explodes over the entire island. His standard attack now becomes a combo with each of the clones slashing once in turn. Meanwhile, the lexicons are spreads out through the island encased in a blue flames. Each of those lexicons support and act as the health of a clone. Destroying a lexicon causes a clone to disappear, and the destruction of the last clone frees all the stolen cards, and Zexion reverts to attacking with his lexicons until he hoards enough cards again. However, even if Riku manages to steal his cards back, Zexion occasionally prepares a countermeasure of sorts by planting a dummy Soul Eater card amongst the scattered pile for Riku to collect. The card is distinguished by "wing" of the blade's design being orange instead of red. If the card is collected then used, it damages and stuns Riku momentarily, giving Zexion an opening to steal cards again.

In Kingdom Hearts II Final Mix, Zexion returns as an optional boss. Zexion's fighting style is totally different however; in the islands, his Absent Silhouette's only attack is to ensnare his prey in his lexicon. However, once they have been captured, Zexion transports them to another dimension where lexicons float around, being conducted by Zexion, who can hide as a lexicon himself. Only the reaction command, Dispel, used on Zexion after depleting his fake HP frees them from the dimension. Meanwhile, they are either bombarded by lexicon copies and explosions, ensnared in life-draining lexicons, or have their commands mixed up. However, if the right commands are selected, HP, MP, Munny balls, or experience points can appear, while another command temporarily removes all the decoy lexicons. His greatest attack involves transporting his quarry into yet another dimension, one which is pitch black save for three spotlights, one of which will be blue. The blue light will rotate between the three lights thirteen times until it comes to a complete stop, after which the entire area will be bombarded by meteors, with Zexion's laughing heard. However, the spotlight where the blue light stops on will be protected by a barrier. Zexion is also forced into the barricaded area, leaving him vulnerable to attack.

In both instances, he is shown to be a particularly powerful opponent, noted by many to be more difficult than Xehanort's Heartless in Kingdom Hearts Re:Chain of Memories Reverse/Rebirth.

Zexion uses a book called a Lexicon, the Greek term for a dictionary. It is apparently named Tome of Judgment. It is unclear exactly what the pages contain, but from what can be seen, it tells some sort of story and lacks a basic dictionary layout. The cover displays three interconnected Nobody symbols. The back bears the outline of another Nobody logo. The spine of the book displays a Roman number six (VI), along with the title "Hallucination - Another Side", superimposed over yet another Nobody symbol. Zexion has the power to trap people within the pages themselves, sending them to a different dimension where he can hide from them and attack. He can also hide himself in the pages.

Bookmaster Heartless also wield books as their weapon, and use spells from their pages. The context of their books may be similar to that of Zexion's.

An accessory based off the lexicon called the "Shade Archive" can be Synthesized in the Final Mix version.