Kernel

The Kernel 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.

Digimon Chronicle X
When the join the  in their fight against the, Seraphimon stays behind to protect the Kernel.