Digitalis is both a virtual dimension and a real planet, originally existing for the purposes of a virtual fantasy game that cannot be physically interacted in physical space. After an incident that took place several decades before X492, the game ended service and the NPCs began to grow self-aware. The NPCs rewrote their programming and began to live in their own virtual society.
In X492, it is still possible to log in to Digitalis by the process of "diving" and creating a virtual avatar. Despite being a virtual world, however, any damage taken inside Digitalis will affect the physical body of anyone harmed while "diving".
The planet is located in a virtual dimension of the Sakura Cosmos.