|15pxAdvent: Celestial Axis|
|Game||Naruto Shippūden: World's Strongest|
|OVA||Birds of a Different Feather, Part I|
|Appears in||Anime, Manga, Game|
|Classification||Ninshū, Space–Time Ninjutsu, Barrier Ninjutsu|
|Hand seals||Snake → Clap Hands Together|
The Advent: Celestial Axis is the central dimension of all of Naoto's Advent worlds and as such is the only one not governed by any set rules. This is where his worlds are born and also where they die. Not many have ever been sent into this world and very few have ever made it out alive. He has stated that this world is where he fights those "he wishes to kill by his own hands".
Unlike his other worlds which almost always are set in a dark forest at night (sans Advent: Path of the Highest, which is set in the day-time.) this world is an open plain stuck in an endless daytime, which expands out into forever. In the center is the World Tree which regulates the chakra needed to control and maintain the worlds. This tree and Naoto are one in the same as the tree cannot exist if he is slain and his worlds are fed by him through the tree.
Unlike with his other worlds where he cannot remove the rules, in his central world he can create any rule he sees fit making him a virtual god-like being while inside his own dimension. The only catch is that it takes a lot of chakra to enact a large number of rules and as such he limits his setting to around 5 at a time.
The tree's branches each hold one of his worlds and at the time, only three exist. At the end of each branch is a sphere that allows anyone within the core world to transport one way (unless it is Naoto or a Space-Time user) to one of these worlds however they will be under the rules of those worlds once they enter.
Upon the unintentional fusion of the Dimensional Counterparts, into the form of Nisshō van Astrea, this dimension was all that remained. It was reshaped by Nisshō to better suit his needs with the assistance spiritually from Naoto.