Sora enters the islands and recognizes them as a place that he remembers. Before he can think too deeply into it, Selphie, Wakka, and Titus run up to him and greet him warmly.
Sora still does not really understand what is going on at the moment as his memory has little left to give him. The three others deduce that Sora must be looking for Naminé, and run off to leave him to it. Sora gains the Key of Beginnings card, and again you take control of Sora. Make your way to the first glowing room on the map, as usual.
After Sora enters the first crown room, Sora runs up and sees Riku. This Riku appears to be the real Riku and is as friendly as before. Unfortunately, Castle Oblivion has taken its toll on Sora’s memory, as Sora barely remembers who Riku is.
During their discussion, a huge rumbling roars through the Island, and Riku reminds Sora of his goal: to protect Naminé, no matter what. Sora agrees and runs off to find Naminé.
Now follow the path to the next special door to trigger the next cutscene. Enter the second special door with the Key of Guidance to witness a devastating weather pattern wreaking havoc on the island. Before Sora can catch his bearings, a rather large Heartless emerges from the water and engages you in (what else?) a boss battle.
Boss Battle: Darkside
First and foremost, do not let Darkside’s appearance fool you. By far, he looks incredibly, impressively dangerous. In reality, this guy is nothing. He is less than nothing. Think Vexen and Parasite Cage rolled into one. This guy has some of the lamest moves for being so ominous looking.
The only thing Darkside has on his side is his enormous amount of defense. He may not have as many health bars as Riku or Vexen, but his tank-like defense is well fortified. Maybe that is why he has lived this long? Darkside’s moves revolve around throwing electric balls at you. He throws blue balls that create more blue balls to hurt you. He also throws blue balls to create little Heartless minions to hurt you. This is child’s play at this point in the game, and should be treated as such. Bring in your best Attack Cards, along with a few Magic Cards, a couple Summon Cards, and some Cure Cards for this fight. He will leave himself wide open for combos and summons, so just target his arms (strangely enough the only places that receive damage) and backhand him back to oblivion. Do not use Sleights, since his arms are usually too high for the Sleight to impact. You will need to do a lot of jump attacks for sure. Once he is defeated, you receive the Darkside Card as a party favor.
Sora and Naminé finally are reunited. But as all good things come to an end, so does this. Naminé tells Sora that he came for the wrong reasons, and a second Naminé appears. The second girl tells you not to believe the other half of her. Sora shows Naminé her good luck charm to prove that he was only looking for her. Suddenly, Naminé turns into Kairi, who Sora had completely forgotten about. Both girls disappear, leaving Sora by himself.
Back on floor thirteen of Castle Oblivion, Sora meets with Naminé again. He exclaims that it is not really Naminé he was looking for, but someone else he cannot remember. Just then Riku shows up and reminds Sora that, in fact, he was supposed to protect Naminé, and that Sora was instead supposed to look after Kairi. In Sora’s twisted memory, however, he cannot remember this at all. As the conversation continues, it becomes quite clear that it is time for the final fight with Riku.
Boss Battle: Riku (Part Four)
Riku has beefed himself up significantly since the last go around. He hits harder than before and is much more ferocious. This fight is simply stunning to behold, as both Sora and Riku are at their most vicious. Riku has a new move called Dark Aura, where he flies around the ring attacking Sora in quick succession, and then ends with the blast wave from his Dark Firaga move.
The worst part of this attack is that it depletes your life bar very rapidly, so it is highly suggested that you bring in around five Cure Cards, and high-level Attack Cards to break this attack before he initiates it. Besides this new move, he recycles his previous moves and has mostly the same pattern as before. Just bob and weave, and combo him when you can and you will be successful. After finishing the level, Sora gains the Riku Replica Card.
Walk up to Riku, and another cutscene begins. Riku blasts Sora to the ground, until Naminé jumps in and knocks Riku down. Larxene enters and explains a bit as to what Naminé and Riku’s relationship is like. Turns out the Riku that you have been fighting has been nothing more than a mere puppet all along. Even with this new information, Sora still stands by his decision to rescue Naminé, which in turn encourages another fight with Larxene.
Boss Battle: Larxene (Part Two)
Like the last Riku fight, this latest battle with Larxene is a bit more challenging than before. This go around she has more life bars and is much more aggressive, sometimes attacking several times before backing off. She also has a new teleportation move, where she disappears and reappears in quick succession and slashes at Sora as she flies back and forth.
Larxene also uses mostly Thunder spells, so try to break these when you can. Larxene has a new move in which long lightning bolts shoot from all directions, trapping Sora in the electricity and raising him up to be beaten back to the ground. This is quite painful.
Besides these overall changes, her fighting style and the tactic to beat her is the same. Break as many of her Thunder attacks as you can and use strong Summon Cards and Magic Cards.
After Larxene fades into nothingness, Goofy and Donald want some answers from Naminé. Naminé explains that Sora’s memories were not truly his own. Naminé put them in his head herself, pushing Sora’s real memories down deep in his mind and creating false memories to go on top of them. After a bit more explaining, Sora decides he does not care that his memories have been false, and then reasons with Naminé to wait where she is with Riku so that he can run to the thirteenth floor. On the way there is another cutscene involving Sora and the gang attempting to remember who was most important to Sora. Once the scene ends, Sora obtains the Trinity Limit ability.