Darkness, but a letter from Kairi summons a gateway for them, and the two are reunited with their friends at their home. Sometime after his first adventure in Disney Castle, Sora discovered a portal at Disney Castle, and ventured through it to find a mysterious armour referred to as 'Lingering Will'. During their exchange, it mistook Sora for Xehanort, after which Sora fought the mysterious armour. Sora won the battle, and the Lingering Will merely knelt down after this, saying that he once felt the power Sora possessed. Sometime later after the events of the game, Sora, Riku, and Kairi receive a letter from King Mickey. The letter, written by Mickey during the events of Kingdom Hearts Coded, describes the parts of their past that Naminé learned while restoring Sora's memory. As they read the letter, they learn of Xehanort's true identity as a Keyblade Master who sought the secrets of the Keyblade War which created their current reality and the fates that befall the apprentices of his friend Eraqus during the events of Kingdom Hearts Birth by Sleep: Terra having ended up possessed by Xehanort and made into the original being of Xehanort's Heartless and Xemnas were split from; Ventus sacrificing his heart by fighting his dark counterpart Vanitas while to prevent Xehanort from recreating the legendary χ-blade which allows the user to control Kingdom Hearts and hiding within four-year-old Sora's heart; and new Keyblade Master Aqua trapped within the Realm of Darkness while an amnesic Xehanort ended up Ansem's apprentice alongside his accomplice Braig (Xigbar's original self). King Mickey also discovers that the destruction of "Ansem" and Xemnas has led to Xehanort's restoration. To combat the new threat Xehanort poses, Sora and Riku take an exam to attain the Mark of Mastery that will allow them to become Keyblade Masters themselves. During the test in Kingdom Hearts 3D: Dream Drop Distance, Sora and Riku enter the Realm of Sleep where they encounter a young version of Xehanort who can travel through time. The two Keyblade wielders also learn how Xehanort has long manipulated events since Birth by Sleep with Organization XIII's true purpose in providing thirteens vessels for him to inhabit and use against seven hearts of pure light in an ultimate battle to recreate the χ-blade. But Sora's interference forced Xehanort to retrieve his alternate selves, Marluxia, Larxene, Demyx, Luxord, Vantias, and Xion from across time in