Zexion
Zexion, the Cloaked Schemer, is number VI in Organization XIII, and the youngest of the original six members. He appeared in Kingdom Hearts:Chain of Memories as a participant in the struggle within the Organization between the newer and veteran members. He was also central to the plot to use Riku as a puppet in Castle Oblivion.
Unlike the other Organization members, Zexion's weapon is unknown, and his talents lie outside of normal combat.
Discovering Riku
After Sora had been lured into Castle Oblivion, Zexion discovered another scent deep in the dungeons of the castle. Originally, he mistook the scent to be that of "The Superior", an (at the time) unnamed entity within the Organization. Eventually, however, Zexion and his cohorts determined that the scent belonged to Riku, who had appeared in the Castle by force of will after Sora arrived. Vexen hypothesized that the darkness in Riku's heart had caused Zexion to mistake him for "the Superior" (Xemnas), calling the effect "fascinating". Specifically, Riku's heart was plagued by the presence of Ansem, Seeker of Darkness. The relationship they shared was that "Ansem" and Xemnas both originated from Xehanort; "Ansem" was Xehanort's Heartless, and Xemnas was his Nobody.
Opposition to Marluxia
Zexion, as well as Lexaeus and Vexen, came to see that Marluxia, keeper of Castle Oblivion, intended to take control of Organization XIII, with the help of Larxene. They decided to oppose the plot by having Vexen investigate Marluxia under the guise of offering to help using the Riku replica he created with combat data from the real Riku. Though they were able to confirm that Marluxia and Larxene were no longer trustworthy, Vexen was eventually killed on Marluxia's orders by Axel, whom Zexion and Lexaeus were unsure about trusting. Axel later told them it was only to gain Marluxia's trust, and continued to cooperate with Zexion in tracking Sora and Riku.
When he discovered that Marluxia planned to manipulate Sora into helping him overthrow the Organization, Zexion decided to follow suit and make similar use of Riku to oppose Marluxia. He sent Lexaeus to sway Riku into joining them, but Riku refused to allow darkness to control him and killed Lexaeus in combat. With the last of his strength, Lexaeus tried to envelop Riku in darkness, but Riku broke free and continued ascending Castle Oblivion.
Confronting Riku
Video
