In Fuyuki City, as an average man, Roy lives a calm and stable life every day that even Kira Yoshikage would envy. Adhering to the principle of staying a step ahead of disaster and running fast enough to avoid trouble, he leads a safe life in this dangerous world. However, his life trajectory begins to deviate drastically after being drawn into the massive magical ritual of the Holy Grail War.
The Avenger known as the King of the Cavern extends a hand to him, and the Magus of Flowers offers applause for his story; the excitement of the tale is just beginning to unfold. The King of Knights, the King of Heroes, the King of Conqueror... stories continue to develop as he encounters countless heroes and writes new chapters of his life.
Since being ordinary can no longer be guaranteed, it's time to start writing his own story.
"The ending of the story will be decided by me."
