Description from original post (created 2012-10-19 19:45):
Riku is effectively the rival and/or best friend of Sora, the main character of the majority of the Kingdom Hearts games. In the first game he was heavily affected and controlled by the Darkness and as a result ended up fighting against or standing in Sora's way throughout the game.
KH2 version: http://www.planetminecraft.com/skin/riku-kh2-1546211/
Reference Picture: