"Sora (ソラ) is a fictional character and the main protagonist in Square Enix's role-playing game Kingdom Hearts as well as its sequels Kingdom Hearts: Chain of Memories and Kingdom Hearts II. His original design was created by Kingdom Hearts series character designer Tetsuya Nomura. Throughout the series, Sora has been voiced by Haley Joel Osment in the English version and Miyu Irino in the Japanese version.
Sora's main weapon is the Keyblade though his primary weapon is the Kingdom Key (キングダムチェーン, Kingudamu Chēn, Kingdom Chain), a type of Keyblade resembling a classic skeleton key approximately 3.5' long, with a long silver keychain extending from the hilt, and a Hidden Mickey token on the end of the keychain. But through using Keychains, the Kingdom Key can assume a variety of unique forms. He is an upbeat, compassionate, kindhearted, and cheerful teenager who, though simple-minded, childish, impulsive, short-tempered, and naïve at times, possesses an extraordinary sense of justice and is always sincere about what he says and does. He originates from Destiny Islands and has been best friends with Riku and Kairi since early childhood.
Sora was not the original Keyblade wielder, but was ultimately chosen over Riku as the true wielder due to Sora's strong heart as compared to Riku's which became vulnerable and temporarily weak due to his turn to darkness. Through out the game series, Sora was referred to as the "Key that connects everything", connecting himself in some way to those he met through his adventures and those who had set up his path. This element is explored in Kingdom Hearts: Birth by Sleep's secret ending."
Source: Wikipedia, "Sora_(Kingdom_Hearts)", available under the CC-BY-SA License.