Throughout his endeavors, Sora is secretly aided by a hooded figure whom Sora believes to be Riku. Following a lead, Sora, Donald, and Goofy enter a passageway to the World That Never Was through Twilight Town, where Axel sacrifices himself to give them safe passage. Sora finds Kairi and Riku, the latter of whose appearance has been changed to that of Xehanort's Heartless after using his power to capture Roxas. Mickey encounters DiZ, who reveals himself to be the true Ansem, Xehanort's mentor. Ansem uses a device that dissipates some of Kingdom Hearts' power, but a system overload causes the device to self-destruct, both engulfing Ansem and miraculously returning Riku to his original form. Atop of the Castle That Never Was, Sora and company battle Xemnas, who uses what remains of Kingdom Hearts to fight them. After Sora and Riku destroy Xemnas, the two become trapped in the realm of darkness, where they discover a portal to the realm of light in a bottled letter sent by Kairi, allowing them to return to the Destiny Islands and reunite with their friends. In a post-credits scene, Sora, Kairi, and Riku receive and read a letter from Mickey, the contents of which are hidden from the player. Development Development plans for Kingdom Hearts II began around the completion of Kingdom Hearts Final Mix, but specific details were undecided until July 2003. Nomura noted several obstacles to clear before development could begin on a sequel. One such obstacle was the development team's desire to showcase Mickey Mouse more, which required Disney's approval. The game was developed by Square Enix's Product Development Division-1, with most of the original staff from the first game. The game was originally supposed to have been released after Kingdom Hearts. Nomura had planned for the sequel to take place a year after the first and originally intended for the events of that year to be left unexplained. To bridge the gap between the two games, Kingdom Hearts: Chain of Memories was developed. To explain the loss of all the abilities from the first game at the beginning of Kingdom Hearts II, Nomura had Sora's memories scrambled in Kingdom Hearts: Chain of Memories. Many aspects of the gameplay were reworked for this sequel. Some changes were made due to user feedback and others were meant to be included in previous games but were omitted either because of time or technological