The Lost Room exists to show you what Ritsuka actually is when no one else is watching. Olga Marie's presence here strips away every comfortable lie the game lets you tell yourself about who you're commanding and why it matters. This is a 50-minute conversation about grief and worthlessness dressed as a supernatural fantasy, built entirely for people who already know what they've sacrificed to get here.

Tucked away in the deepest part of Chaldea is the Lost Room, a forgotten space that belongs to nobody. There, one can glimpse what has been lost, or perhaps what time will take away. Lit by moonlight, the room sits on the border between dream and reality. The Chaldea Summoning System created it, and it offers a handful of modest benefits. This one-episode action fantasy special adapts the Prologue to Arc 2.0 of the Fate/Grand Order smartphone role-playing game.