sentences:  Returning to the World That Never Was to stop Xemnas' plan as per Xion's last request, Roxas encounters Riku, who attempts to capture him for DiZ and resume Sora's memory restoration process, which has completely halted.When Roxas overpowers him, Riku releases the darkness suppressed within his own heart, giving him the power necessary to subdue Roxas, but also giving him the physical form of Xehanort's Heartless, Ansem, who resides in his heart.DiZ inserts Roxas into a virtual simulation of Twilight Town without any of his memories of the Organization so that Roxas may eventually merge with Sora.