Riku Replica

Riku Replica is a direct copy of Riku who appeared in Kingdom Hearts: Chain of Memories. Riku Replica, as his name implies, was created via Sora's childhood friend, Riku's combat data. Originally a subject to test out Riku, Riku Replica was later exploited to become a puppet of Marluxia, attempting to use Riku Replica to manipulate Sora and overthrow the Organization.

Creation and purpose
Riku Replica was first sent by Vexen as a subject to test out Riku's strength, and hopefully, letting Riku's Heart submerge into the Darkness again, Riku was first shocked to see his counterpart, however, the duo ignited a battle after the original hears Riku Replica's taunts. Due to the time being of Riku Replica's existence, he lacked the experience and was quickly beaten down by the original Riku. Riku in return attempts to destroy the Replica, but nonetheless failed when Riku Replica utilized the power of Darkness.

Sora's storyline
Riku Replica escapes, and eventually ends up in the Organization's head floor, Larxene taunted Riku Replica for his loss, however, the replica denied his failure, saying that his powers have not grown enough. However, the organization members later changes their plans, hoping to turn Sora into their puppet and overthrow the Organization. Larxene suggested that should Riku Replica's memories were rewritten to be the exact as the original's he would become much stronger, and much of a useful tool.

Riku Replica, upon hearing Larxene's resolution, rejected, saying that he does not want the original's pitiful memory, however, all the members began to agree upon Larxene's plan, fearful that he would loss his memory, Riku Replica assaulted Larxene, however, he was quickly knocked unconscious, and Naminé was ordered to rewrite the replica's memory.

After having his memory fully rewritten, Riku Replica swore to protect Naminé, and sees Sora as a threat. Sora's first encounter with the replica confused the Keyblade master, however, Sora managed to defeat the replica, who then escapes. Riku Replica later encountered Sora in Castle Oblivion's 8th floor, where he urges Sora to leave, as he would protect Naminé, hoping to regain his friend's memory, Sora offered to jog Riku Replica's memory, but nothing worked, and a fight ensues. Riku Replica, defeated, felt even more anger when Sora offered his help to protect Naminé together, filled with rage and jealousy, Riku Replica spurted his true feelings upon Sora, and angrily runs away. Riku Replica's third encounter with Sora happened in the 12th floor, where he aggressively urges Sora to leave, Sora, who defeated Vexen tells his friend that he's free, blinded by rage, Riku Replica lashes back at Sora, and tells that the Keyblade master's lucky charm was a fake, and the lucky charm he holds is the real thing. Sora and the replica fought, however, Riku Replica was once again defeated, and runs away.

Riku Replica's false memories comes to an end in the 12th floor of Castle Oblivion, meeting again with Sora, he stated that he was the one destined to protect Namineé but Sora's wrecked memories keep interfering. Sora defeats the replica, however, when Sora was about to help him, the replica retaliate, knocking Sora back, just as Riku Replica was about to to deliver the coup de grâce, a desperate Naminé shatters Riku Replica's farce memories and his Heart. Larxene later interferes, and explains Riku Replica's nature and creation (note that until this was revealed the Riku Replica was believed to real thing by Sora, as well as the player as it wasn't revealed that he was a copy), an angered Sora fought with the organization member, successfully defeating her. Riku Replica was last seen in the top floor of Castle Oblivion, where he saves Namine from Marluxia's captive, despite losing his memory, he remembered his oath-to protect Naminé. He protected Naminé throughout the battle between Sora and Marluxia. In the end, he leaves Sora and co. stating a fake like him does not deserves to be together with them, however, Sora comforts the replica. Feeling Sora's warm comfort, the replica smiles and leaves. But he still has one more thing to do-defeat the real Riku.

CoM manga
Riku's replica never fights the real Riku and is not killed. However, he encounters Riku, and tries to make himself look taller. When Riku blatently ignores him, the Replica visits Vexen's grave, where he encounters Vexen clones, who keep following him. He also takes a bit off a piece of a rice cake, and puts a chain on it, pretending that it's a "new good luck charm." Referring to Naminé giving him the fake luck charm.

Reverse Rebirth
After leaving Sora, he joined Axel, a member of the organization, they both seek the wounded Zexion, where Zexion was shocked to see Riku, but was later relieved to know that the "Riku" he saw was just a fake. The wounded organization member's relieve does not last long, however, when Axel influence the replica with his words, telling him should he regain new powers, he could be something original, not someone's counterpart. Agreed, Riku Replica approaches Zexion, and drains thre lifeforce out of him. Riku Replica was later seen in a memory stimulated Twilight Town, where he meets the real Riku in the abandoned mansion. The replica remarks that Riku no longer feared the Darkness, in which earn the original's confusion in return. Riku Replica replies that he is Riku, and thus he would know everything about his counterpart. Feeling annoyed, Riku remarks that he is himself, and no one could possibly be him. Angered, Riku Replica taps in his Dark powers, and states that in the end, he was still a replica, even after gaining new powers, he was still nothing more than a replica. Blinded by jealousy and rage, Riku Replica engaged the original, and the two put up a fierce fight. In the end, despite Riku Replica's newfound powers, he was defeated, and slowing fades back into the Darkness. In his dying breath, he questions Riku where would a replica's heart like him go, Riku comforts the replica, stating that it would go to the same place as the original. The replica smiles, and remarks "How original." before fading back into the Darkness.

In Combat
The Riku Replica fights with the same style as the real Riku, but his sleights take less power than Riku's. For example, Riku can only use Dark Aura with three 9's, a total of 27. However, the Replica can use any three cards, say 4, 7, and 8 to perform Dark Aura. He is also more aggressive, which leads to some open moments during his battles.

Card
See: Riku Replica (Enemy Card)

Personality
The Replica is more aggressive and protective than Riku, which is exactly what Xehanort's Heartless was looking for. He is also more stubborn. At the end of his life, the Replica became much more like the original, he became sullen and mellow. He was quick to anger, and often lashed out at anyone who talked back to him, even if they overpowered him. He seemed to be as powerful as Riku was at Hollow Bastion, when under Ansem's Possession.