Riku, who has returned to his older body, and Mickey take a still-asleep Sora back to the Mysterious Tower, where they tell Yen Sid about Xehanort's plan. The elderly Master tells Riku that since he managed to open the Sleeping Keyholes, he should have learned the Power of Waking, which he can use to save Sora's heart from the darkness. Mickey volunteers to do it instead, but Yen Sid points out that Riku stands a better chance of succeeding since he was already in Sora's heart before. Riku opens a portal into Sora's heart and dives inside. After descending down into his Station of Awakening, he finds himself in a dark abyss. Ventus's Keyblade Armor, still tainted by the darkness, emerges as the Armored Ventus Nightmare. Riku manages to defeat it, freeing Sora from the darkness.
Riku attempts to leave Sora's heart, but he finds himself at Destiny Islands, where he meets illusions of Roxas, Ven, and Xion, the latter whom he doesn't remember. The three illusions ask him questionsnote , after which a bottle washes up on the shore. After picking it up, Ansem the Wise appears. He tells Riku that he left a digital copy of his research inside Sora's heart, which hopefully can be used to help them find their lost friends. Ansem the Wise expresses his hope that due to the bond he has with other people, Sora can bring his lost friends back. He tells Riku that Sora was woken up when the Armored Ventus Nightmare was defeated, so Riku returns to the real world.
Back in the Mysterious Tower, Riku wakes up to find Sora is already back. When he sees Riku awake, Sora is relieved. He tells Riku that he heard his voice in his dreams. Yen Sid reveals to the two boys the results of the Mark of Mastery exam. Riku finally becomes a true Keyblade Master, but Sora fails. Since he came so close to falling into the darkness, Sora still lacks the control necessary to become a Master. Lea tells them that he wants to become a Keyblade Master as well, but he's still learning. He suddenly manages to summon a Keyblade of his own, much to everyone's surprise.
After the announcement of the results, Sora returns to Traverse Town, where he meets all the Dream Eaters that helped him along his journey. He plays with them for a while, and his happiness causes his heart to connect with Ven, whose body is still in Castle Oblivion. Ven smiles after sensing how happy Sora is.
In a secret ending, Aqua is standing on the Dark Margin in the Realm of Darkness, hoping for an end to her suffering soon. Meanwhile, Yen Sid sends Riku on an important mission. He then summons Mickey to speak to him. He tells Mickey that Xehanort plans to use the Princesses of Heart as a backup if the Guardians of Light refuse to fight him, which means that they cannot simply refuse to fight the Organization or else the princesses will be in danger. They ponder on who the last Guardian of Light could be; they were missing two, but with Lea they just need one more. Just then, Riku returns with Kairi. Yen Sid tells her that he plans to make her a Guardian of Light since she has the ability to wield a Keyblade. He arranges for her to begin training. Soon the time will come: the Keyblade War will be fought, and the χ-blade will be forged. As the conflict draws near, the fate of all worlds hangs in the balance.
Tropes:
- Call-Back: The Armored Ventus Nightmare fights almost exactly like Ven. It holds Sora's Keyblade in Ven's Reverse Grip, and imitates Ven's Fever Pitch combo, Aeroga, Reversal, and the Firestorm finisher.
- Cutting Off the Branches: When diving into Sora's heart, one of his memories that Riku passes by is of him fighting the Darkside at his first Dive to the Heart. He's wielding the Dream Sword in this memory, confirming that he canonically chose to follow the Power of the Warrior.
- Fighting Your Friend: Riku versus Sora has been a thing throughout the series. Except this time, you're playing as Riku, and it's Sora who's possessed and serving as the boss.
- Kaizo Trap: There is only one correct way to answer the questions asked by Roxas, Ven, and Xion to obtain the secret ending. Answer wrong, and the secret ending is out of reach (the first time around, that is).
- Post-Final Boss: With Young Xehanort feeling more like a proper final boss, the Armored Ventus Nightmare feels more like a denouement.
- Wham Shot: Lea has a Keyblade now.
