The Final World

The Final World is an original world in Kingdom Hearts III.

Kingdom Hearts III
When Sora began his Dive to The Heart, he fought a transparent, glass-like Darkside.

After Sora, Donald, Goofy, Riku, Kairi, Aqua, Ventus, and Mickey were consumed by a Tornado of Heartless, Sora ends up in a flat reflective plane, similar to the one he was at when fighting the Darkside at the Station of Awakening. After wandering through the area, a light came down, revealing itself to be Chirithy. Surprised as to why Sora still has a psychical form, although transparent, it states that Sora and his friends were being tethered to the Realm of Light, thanks to the help of Kairi. Chirithy states that Sora needed to collect the "pieces" of his body, in the form of him walking around and doing other actions, that are scattered throughout The Final World. After collecting the first ten, a portal to a labyrinth appears, alongside nameless stars. These nameless stars are all that remains of those hearts that are still tethered to the Realm of Light, but without a body.

Among the nameless stars, there was Naminé's, she explains that she was sent to The Final World when Kairi was struck by a powerful darkness, she informs Sora that Kairi was the one keeping him from fading away. She found Terra and tells that she will trace him and help "tip the scales in the other direction", allowing the Lingering Will to help fight off Terra-Xehanort once Sora returns to the Keyblade Graveyard.

Sora then meets another notable nameless star, who says they were stripped of everything but their heart, as they wait for someone whose has been changed beyond recognition, as "his heart changed for another's". Sora asks about what kind of person resulted in her current form, thinking that it could be a Nobody, but the star only alludes to it being a "somebody". Offering to help the nameless star find the person it is waiting for, Sora asks for their name, and the nameless star whispers it to him.

After completing the rest of his body, Sora then asks why Chirithy is there. They reply that they are waiting for "someone". Sora then asks how to save his friends, and is answered by a snarky remark at not knowing how to "restore people's hearts". Sora realizes that he must use the power of waking to rescue his friends, as Chirithy instructs him to "look for the light in the darkness".