Manaka Sajyou, an existence connected to Akasha, is unable to experience phenomena like change and surprise, so she wishes to attempt to "dream." She sends her consciousness through the Reverse Side of the World, beyond the end of the world, and into different times and different space. During the transfer, she sees a dragon waiting for another for a very long time, sees light shining at the end of the world, and ends up in a one-room apartment that seems like the Root. After leaving the apartment, she ends up in a labyrinth hosting a variant Holy Grail War featuring four Servants and Masters attempting to reach the bottom. Manaka has possessed the body of Norma who has summoned a female King Arthur compared to the male Arthur of her world. Saber interacts with Manaka, and Manaka and Norma see each other when looking in a mirror.
- Manaka Sajyou
- Saber/Arturia's Master. Omnipotence becomes the “girl”. She is a far eastern magus. In “Fate/Prototype Blue Silver Fragments” she fights as Saber (Arthur Pendragon)’s Master, but before she knew it, her consciousness had possessed Norma’s body. She controls Norma Goodfellow's body for the first half of the novel.
- Norma Goodfellow
- A female magic user, and an explorer who collects relics by visiting various unexplored regions at the request of the Mages Association. She is in her mid-teens. She has a habit of naturally “running into” mysteries and illusions, and is the carrier of the fairy eyes (Glam Sight). She is initially the person summoning Saber before Manaka ends up taking over her body. She serves as the main narrator for most of the novel.
- A Servant summoned into the swordsman class. In legends, she is a British patriot hero known as “King Arthur.” Her real name is “Arturia Pendragon” and she is a woman. (She participates in the war from “Fate/Stay Night.”)
- A Servant summoned into the magician class. She is a mysterious woman who covers her head with a hood. She is spoken of as a treacherous witch and is a princess of Colchis. Her real name is “Medea.” (She participates in the war from “Fate/Stay Night.”)
- A Servant summoned into the assassin class. He is the founder of the Assassin Order, and his real name is “Hassan-i-Sabbah.” For the many present he is called the “Hassan of the Cursed Arm.” (He participates in the war from “Fate/Stay Night.”)
- A Servant summoned into the bowman class. A keen and nimble man who wraps his body in green lightweight armor. He is a rebellious hero, and is a legendary thief in Britain. His real name is “Robin Hood.” (He participates in the war from “Fate/EXTRA.”)
- A girl said to be conducting an investigation into this mystical cavern. She carries a huge scythe, and she personally calls herself “weak.” Norma has a hunch that she is a Servant, but……?
- Wolfgang Faustus
- A man with beautiful features, who acts in an elegant and noble manner. However, he is mysterious and somewhat eerie, and the people who have met him describe him as “a devil dressed in black.” He serves as the main antagonist for the novel.
The novel was serialized during the period between the end of part three of Fate/Prototype: Fragments of Sky Silver and the beginning of part four.