Kernel
The Kernel (中核カーネル, ChūkakuKāneru?) is both the Digital World's core and the domain of its God. It is the three Celestial Digimon's primary duty to defend the Kernel. Rasielmon possesses the mysterious power to foresee everything in the world from the Kernel. It is said that it knows all about events throughout the Digital World, and has gained a divine amount of knowledge with that power.
Fiction
Digimon Chronicle X
When the Celestial Digimon join the Royal Knights in their fight against the Seven Great Demon Lords, Seraphimon stays behind to protect the Kernel.
Digimon ReArise
The Kernel contains all information about the Digital World, both past and future and is referred to as God's Territory, with Angel Digimon protecting it and hiding it from anyone else being able to access it. If anyone were to access it, its power is so vast it could even be used to remake the entire World. The End of the Road: Eiji's Fulfilled Wish Humans, Digimon, and Spiral are unable to use its powers to their full extent however – this ability lies only with Gods.
Rasielmon is able to see the future and witness all things in the Digital World due to the power imbued in it by the Kernel.
After Eiji is able to get into the Kernel by using the power of the Spiral and the DigiCores of the Four Holy Beastss, he is able to use its power to look for the information he wants. When the Protagonist, Rasenmon, Mon, and Jesmon arrive and confront him, he ends up playing the information which causes his mother's memories to play. After freaking out and learning that his mother had died after giving birth to Mon (with both learning they were related) one of the Spiral working with Eiji attack him during his break down and take over the Kernel, its plan all along being to take it over so it could use the Kernel's power to destroy both the Human World and Digital World as revenge for them persecuting the Spiral. The Spiral were originally a hive mind, however this one had glitched and gained its own sentience and named itself Spiral Origin. Jesmon and Rasenmon try to stop Spiral Origin, however now having the power of the Kernel it easily defeats them, banishes them out of the Kernel, then begins its plan to destroy both Worlds.
The Tamers eventually break back into the Kernel by hacking Herissmon and using its connection to the Spiral Hive Mind to allow them to travel to where Spiral Origin was, despite the Kernel itself being otherwise inaccessible. As the Tamers travel the Kernel, they are ambushed by stronger and stronger Spiral until they eventually reach Origin. Origin spawns even more Spiral, with everyone except Rasenmon fighting them. Rasenmon tries to talk Origin down and as it does, it is given power by rebellious Spiral who didn't want Origin to destroy the World and instead wanted to be friends with everyone (as Origin was unable to exert its will over the entire Hive Mind at that point). Origin uses the ones it still had control over to become its own unique form, though the rebellious Spiral power up Rasenmon up enough to allow it to defeat Spiral Origin. This also causes the Spiral Guardians fighting in the Dark Area to disperse as well.
After Spiral Origin's defeat, the Three Archangels return to the Kernel and usher everyone out with the exception of Eiji and Spiral Origin as their data had been altered due to taking control of the Kernel. Due to them doing this, both the Digital World and Real World would reject them, meaning they were now trapped in the Kernel forever though Cherubimon stated they would both be deleted as punishment for their actions once they had regained control of it (though had no clue how long this would take, as the duo had done large amounts of damage to it meaning it could take "all eternity" to fully fix it). Eiji didn't care about the fact he was trapped there, as he no longer had any reason to want to return anyway since he had achieved his life goals and simply decides to wait for his fate to be sealed. He ends up creating a program allowing the Spiral to turn into real Digimon, though Spiral Origin wasn't included in this and remained trapped forever with Eiji.
