Zexion

Zexion is number VI in the Organization. His skills lie outside of normal combat. He is one of two Organization members who appear only in Riku's story. He has the ability to identify individuals by their scent and is able to sense when they die by noticing their scents fading, and seems to be able to do so from great distances. He can also shapeshift. His element is illusion, allowing him to mimic others' weapons and create duplicates of himself. He has his own weapon, yet it is currently unknown. Zexion informs Vexen and Lexaeus when he senses two new scents in the lowest basement of Castle Oblivion. One of the scents is Maleficent, and he senses that she is eliminated by the other visitor, one with a scent "exactly similar" to that of Xemnas (referred to as the Superior). With little information on what was happening, he and the others decide to await development. Not long after, he identifies the other guest in the castle: Riku. He observes the boy's progress through Castle Oblivion until Vexen's death, when he and Lexaeus decide that they should use Riku just as they believe Marluxia will use Sora.

After Larxene, Lexaeus, and even Marluxia are killed, Zexion sees that Riku is no longer needed and attempts to destroy Riku himself. He does not plan to use brute force, though, partly because of personal preference, and partly because Riku already defeated Lexaeus, one of the stronger Organization members. He leads Riku into a manifestation of Destiny Islands, Sora and Riku's home, in which Riku sees his friends disappear without saying a word. Zexion appears and wages psychological war on Riku, telling him about how he threw away his friends and his home, opened the door to darkness, and destroyed his islands. Following Riku's battle with a Darkside Heartless, Zexion uses his power to disguise himself as Sora and attacks him, telling him that he's become nothing more than a pawn of the darkness. He engulfs Riku in light, but a vision of Kairi (who is actually Naminé in disguise) manages to convince Riku to shed his fear of the darkness and accept both it and the light. With newfound strength, Riku follows Zexion's dark scent through the light and strikes him, but Zexion escapes. His escape is short-lived, however, as Axel brings the Riku Replica down to him and convinces the replica that he can become real by gaining power that the real Riku does not have. The replica agrees, and per Axel's suggestion, kills Zexion.