Originally Posted by
Comun
Intentional Servant summoning is still entirely dependent on Justeaze's squished not-dead corpse, which only exists one of. FsN and FZ kept in Fuyuki, Apo took it elsewhere, FGO and Requiem required the implied main villain to win the Fuyuki Grail first to make Servants readily available, Prototype and Redline's worlds explicitly not share their basis with FsN, and EXTRA is a weird ball of unknowns but Servants definitely aren't summonable on Earth now. FsF is the one that comes closest to your description, but even that took 60 years and could easily be countered by delaying the ritual for a week.