Riku

Riku's History
A resident of Destiny Islands and best friend of Sora, Riku inherited the power of the Keyblade from Terra, a Keyblade-wielder visiting the Islands. As he grew older, Riku began to long for a way off his homeworld, and a way to visit other worlds. To accomplish this goal, he, Sora, and their friend Kairi set about building a raft with which they hoped to sail to other worlds. However, before they could set out, their world was attacked by the demonic Heartless, who consumed the world. Riku was swallowed up by the darkness seconds before he was supposed to gain the power of the Keyblade, and it went to Sora in his stead.

Transported to the refugee world of Traverse Town, Riku was excited to finally see another world. Soon, he came across Sora, who had been fighting against the Heartless with the aid of Donald Duck and Goofy. It wasn't long before Riku discovered that Kairi had gone missing during the destruction of their world, and Sora had been searching many worlds to find her and Riku. Sora offered for Riku to accompany them on their journey, but Donald refused to let him. Riku left before the argument could be settled.

The evil sorceress Maleficent, who was using the Heartless for her own ends, came across Riku at this point, fostering feelings of rejection and hatred within him. Riku allied with her when she told him she would help him find Kairi, who Riku had feelings for. Soon, however, Riku found out that Kairi had apparently lost her heart, and he fell in further with Maleficent in an effort to reclaim it. He was given control over the darkness, clashed several times with Sora, and ultimately was possessed by the spirit of "Ansem", creator of the Heartless.

Sora eventually slew Ansem, and Riku redeemed himself by helping to close the doors to Kingdom Hearts, preventing a massive invasion of Heartless into the Realm of Light. He was trapped behind the doors, and eventually came to Castle Oblivion, where he clashed with the fiendish Organization XIII, as well as fighting the lingering effects of Ansem's possession. Initially trying to resist the darkness inside him, Riku eventually learned to accept a balance between the darkness and light.

Riku came to become an agent of the enigmatic DiZ, capturing the Organization member Roxas to help Sora, who had lost his memory in Castle Oblivion. Riku once again fell prey to the darkness, and was changed into a doppelganger of Ansem, but was ultimately restored, and helped Sora destroy the Organization once and for all.