The following characters are wielders of the Keyblade:
The Keyblade chooses
Yes, Kairi became a Keyblade Weilder by touching her Keyblade (I think.)
Kingdom Hearts III: The Keyblade Wars isn't an actual Kingdom Hearts title. This confusion is all caused by the fan-made box art cover for a contest on the internet. Kingdom Hearts III: The Keyblade Wars has never been mentioned, discussed or announced by Tetsuya Nomura (character designer/director) or Square Enix. The newest title in the Kingdom Hearts series is "Kingdom Hearts 3D" (tentative title), which isn't being regarded as "Kingdom Hearts III".
king Micky is the king of Disney castle on kingdom hearts series. He is one of the key blade wielders.
The Keyblade itself is not real, it was invented for the Kingdom Hearts video game series. However, Kingdom Hearts fans like to make life-size keyblade replicas out of various materials, ranging from cardboard to metal (depending on how much time/money they want to spend on it).
Kingdom Hearts III: The Keyblade Wars isn't an actual Kingdom Hearts title. This confusion is all caused by the fan-made box art cover for a contest on the internet. Kingdom Hearts III: The Keyblade Wars has never been mentioned, discussed or announced by Tetsuya Nomura (character designer/director) or Square Enix. The newest title in the Kingdom Hearts series is Kingdom Hearts 3D: Dream Drop Distance for the Nintendo 3DS, which will be released in North America and Europe in late July. Kingdom Hearts III has recently been anounced as "in production."
Riku is in Kingdom Hearts because he is one of Sora's friends on Destiny Island, and an important character in the series.*Slight Spoiler*As we later find out, Riku's destiny was written when he was chosen as a Keyblade-wielder, during the events of Kingdom Hearts Birth by Sleep.
A replica of Sora's Keyblade or any of the Keyblades in the Kingdom Hearts series for that matter, can be found rather easily on sites that also carry replicas of swords or collectibles of that sort. The best sites to find items related to Kingdom Hearts are cosplay websites because they are often specialized in certain anime and video game character outfits and the props that go with them.
Kingdom Hearts 3 is not yet in developement. However, from statements made by the designers, Kingdom Hearts Re:Coded and Dream Drop Distance will set up Kingdom Hearts 3, which will include Sora, Roxas and Kairi and will be a culmination of the Keyblade destinies that are hinted at in Birth By Sleep and the rest of the series. However, this is mostly speculation and no specific information has been released officially.
It is a Kingdom Hearts game, but not important to the series.
Riku's primary weapons, although sword-like, are in fact Keyblades. He uses both the Soul Eater and Way to the Dawn Keyblades in the Kingdom Hearts series, both of which resemble swords. In the Mission Mode of Kingdom Hearts 358/2 Days, when you play as Riku, every weapon panel makes his weapon the Soul Eater, while the Zero Gear gives you Way to the Dawn.The only other Keyblades that Riku are seen with are the Keyblade of People's Hearts (also known as the 'Dark Keyblade') and the Oblivion Keyblade.
Sora's first keyblade is the Kingdom Key, which Sora uses to fend off the heartless during the events of the first Kingdom Hearts game in the series. The night before Sora, Riku and Kairi go on their planned adventure, a storm happens and heartless start to appear all over their homeland Destiny Islands. Sora, unable to hurt the heartless with his wooden sword, looks down at his hand and sees the Kingdom Key keyblade materialize. This is the first we see of any keyblade.