Filled With Online system for FoundryVTT, based on the English releases (translated by Ishkander) and Project FW's site (Japanese only).
After Earth is ravaged by attacks of unknown origin, humans living on spaceships who long for its blue skies and green pastures log in to Filled With Online, years after its official closure. There, they find artificial intelligence capable of growing and learning as humans do.
After all of humanity's greatest heroes (the players) have disappeared, Filtwith's human civilization must continuously fend off assaults by the demonic races, defending a major defensive chokepoint they know as the "Great Walls".
This includes character sheets, basic stat calculations, and buttons for handling common rolls and damage calculations.