A second world lies behind the one that we know, hidden away behind a thin curtain of lies and secrecy. It has been thousands of years since the Age of the Gods, and the modern era has stripped much of the world of its mystique, but magic stills exists, as do Heroes, and the men and the beasts that necessitate their existence.
Magi hoard and jealously protect centuries of thaumaturgical lore, and fell beasts prey upon human society from the darkest corners of the world. Ill-considered gladitorial rituals cast a long, bloody shadow upon unsuspecting cities, and malignant gods fester and grow to consume them.
It's nearly ten years since the Fourth Holy Grail War ended in failure, and those who seek the Holy Grail have begun their preparations to seize it once more. The seven Heroic Spirits who will fight as Servants Saber, Lancer, Archer, Rider, Caster, Berserker, and Assassin await their summoning in the Throne of Heroes, and the magi who will be their Masters scheme and plot. The Cup of Wishes awaits the last pair standing.
None realize the only wish it can grant is disaster.
This is a custom Fate/Stay Night theme based on the events of Fate/Stay Night: Realta Nua. Unification occurred before the Grail War, which is still pending. What FCs are up to is entirely up to applicants and should be discussed with existing cast, as this theme exists specifically to differ from the ordinary canon - so, every FC is actually an OFC.