- "Behold, this town... Once a seat of power for all Keyblade wielders. It is the nexus from which all worlds spring. Here, I and my other selves can be one. United... in Scala ad Caelum."
- —Master Xehanort
Scala ad Caelum, also known as Stairway to Heaven is an original world introduced in Kingdom Hearts III. As a world built over the remnants of Daybreak Town, it is believed to be the nexus from which all worlds spring, having once served as a seat of power for all Keyblade wielders.
This world is composed of a constantly sunny sky, with an immense ocean, just like The Final World. Across this vast ocean are a quasi-infinity of mountain citadels and buildings, which are each connected to each other by a tram system found on each mountain.
However, underwater are what appear to be the "inverted ruins of Daybreak Town." Much of the final fight against Master Xehanort seems to unfold around the dilapidated remains of a Clock Tower similar to Twilight Town.
Before Kingdom Hearts
Inside the main citadel, two young apprentice Keyblade Masters, Xehanort and Eraqus in their youth, play a board game similar to chess: Xehanort uses black and gold pawns, for the Thirteen Seekers of Darkness; Eraqus uses white and silver pawns for the Seven Guardians of Light and the Dandelions.
At one point, Xehanort talks with Eraqus about "their Master's favorite story": the First Keyblade War. But Eraqus feigns ignorance when Xehanort evokes with conviction the "lost" Foretellers, who were at the origin of this war. Xehanort then looks up at the Keyblade Gazing Eye, and talks about the conclusion of the War: "The war in that place will lead to the defeat and destruction of the Light. The World will be enveloped in eternal Darkness." But Eraqus then tries to convince him that the Light was always more complex than it seems, including the "Light of the Past". Xehanort can not help but be curious about this possibility.
After the defeat of Xehanort against Eraqus, the latter proposes a new game in which are staged: seven black and gold pawns, for the Master of Masters, Luxu and the Foretellers, and a single white and silver pawn for Sora.
Kingdom Hearts III
At the Keyblade Graveyard, after the reforging of the χ-blade and the opening of Kingdom Hearts by Xehanort, Riku and King Mickey conjures up the idea of old Master's Time Travel power to "trap him out of Time and Space". While Ventus, Terra, Aqua, Riku, Mickey, Xion, Roxas, and Lea open Xehanort's portal, Sora, Donald and Goofy are volunteers to defeat Xehanort once on the other side, leading them to Scala ad Caelum.
The trio begins by exploring the main citadel and notices what appears to be Replica Xehanorts, appearing in many different places. After defeating them, Xehanort finally shows up, describes to them Scala ad Caelum as the source of the Power of the Keyblade and all the worlds of the Realm of Light, and begins to absorb his Replicas to put on a gigantic goat-shaped Keyblade Armor, and with the Gazing Eye as his weapon. A great clash follows, where Xehanort seems able to completely distort the reality of this world on the Trio. However, Sora breaks Xehanort's armor, and the fight continues at the top of the main citadel.
For his final confrontation with Sora, Xehanort finally wields the χ-blade and manages to defeat him by using the power of Kingdom Hearts. But the young Keyblade elect manages to recover with the help of Donald and Goofy, which causes the defeat of Xehanort.
Despite his defeat, the old Master remains clinging to his positions, until Eraqus' heart, having survived in Terra's body, persuades him to capitulate. Finally, Xehanort recognizes his defeat and gives the χ-blade to Sora, to "reward" him, before joining Eraqus in the afterlife ...
- Scala ad Caelum is Latin for Stairway to Heaven.
- During the development of Kingdom Hearts III, Scala ad Caelum was known as Cable Town and had only been shown to fans once, during a private event for the launch of Kingdom Hearts HD 2.5 ReMIX in December 2014.
- The world was publicly unveiled during the trailer "Final Fight", four years after its presentation to fans.