It is my belief that riku has tied inheritance to terra's keyblade and MX's keyblade nomura has implied that when Xehanort's Heartless possessed riku and was then removed that a part of terra remained within him. I think he left xehanorts keyblade as well as the memory of his own. It is possible that when riku fully delved into his powers of darkness he awakend the potential to wield MX's key blade because the keyblade is an tied to the weilders heart it used soul eater as a intermediary forming the way to dawn(This would explain why it has the same eye as MX's keyblade). Now similar to xion, I think riku can wield a second keyblade baised on the memories of terra's keyblade. considering where riku's last memory of the terra's keyblade took place it seems natural that it takes form of destiny's place. I think when riku wakes his power of sleep he will fully awaken terra's keyblade and Xehanort will reclaim his
It is my belief that riku has tied inheritance to terra's keyblade and MX's keyblade nomura has implied that when Xehanort's Heartless possessed riku and was then removed that a part of terra remained within him. I think he left xehanorts keyblade as well as the memory of his own. It is possible that when riku fully delved into his powers of darkness he awakend the potential to wield MX's key blade because the keyblade is an tied to the weilders heart it used soul eater as a intermediary forming the way to dawn(This would explain why it has the same eye as MX's keyblade). Now similar to xion, I think riku can wield a second keyblade baised on the memories of terra's keyblade. considering where riku's last memory of the terra's keyblade took place it seems natural that it takes form of destiny's place. I think when riku wakes his power of sleep he will fully awaken terra's keyblade and Xehanort will reclaim his