Does Riku have a Nobody? (Possible spoilers)

[PuPu]

Riku never actually succumbed to the darkness. In fact, he was able to perfectly control it without letting it take over his heart throughout the entire series up until when Ansem the Wise's machine blew up. That's why he never became a Heartless.

Sure, Xehanort's Heartless may have took over his body, but he didn't take over his heart. Riku kept on fighting him until he managed to beat him and control his power as well.