Riku is the orginal keyblade master.
My reasons are:
1) After you seal the keyhole in Neverland, a short clip shows a young Riku and Sora in the Secret Place at Destiny Islands. Right before Riku follows Sora out of the cave, the keyhole of Destiny Islands reveals itself to him on the big door. Why would it reveal itself to Riku and not Sora? Hmmmmm.
2) In Jiminy's Journal, it says:
"When Kairi lost her heart, Riku allied himself with Maleficent to save her. Riku was actually the rightful master of the keyblade, but once he chose darkness over light, the weapon chose Sora instead. Ansem exploited Riku's weakness of heart and possessed him."
My reasons are:
1) After you seal the keyhole in Neverland, a short clip shows a young Riku and Sora in the Secret Place at Destiny Islands. Right before Riku follows Sora out of the cave, the keyhole of Destiny Islands reveals itself to him on the big door. Why would it reveal itself to Riku and not Sora? Hmmmmm.
2) In Jiminy's Journal, it says:
"When Kairi lost her heart, Riku allied himself with Maleficent to save her. Riku was actually the rightful master of the keyblade, but once he chose darkness over light, the weapon chose Sora instead. Ansem exploited Riku's weakness of heart and possessed him."