Mystery By Moonlight

運命のルーレット廻して

アレコレ深く考えるのはMystery

「運命のルーレット廻して」（Zard)

Turn the roulette of destiny

Thinking deep about this and that is a mystery

"Turn the Roulette of Destiny" (Zard)

The Fate series is a long-running multimedia franchise, which started with the fantasy game Fate/stay night in 2004. Since then, it has seen numerous installments in various forms of media, from games, to anime, manga and novels. Some of these installments are direct sequels/prequels in the same chronology, some involve alternate universes/retellings, but in general, the series revolves around a series of events called the Holy Grail Wars, with persons called Masters fighting each other with the help of Servants, spirits/familiars based on figures from history, mythology and fiction from all across the world like King Arthur, Ramses II and Sherlock Holmes. This is in fact basically all I know about the Fate series: while I naturally knew of its existence (it's really popular), I had never consumed any part of the franchise yet. At least, not until this week.

The most popular incarnation of the Fate series these last few years has been the smartphone game Fate/Grand Order, which started in 2015 and ranks amongst the most popular mobile games in the world: in 2017 it became the sixth highest-grossing mobile game, leaving titles like Pokémon Go and Candy Crush Saga behind. I don't play the game myself, but my interest was piqued when in May 2018, a special limited quest event started, with the title Murder at the KOGETSUKAN. What first caught my eye was that the event was penned by Van Madoy, who since a few years has been chiseling out a niche for himself by writing original mystery novels for existing game franchises (like Gyakuten Saiban/Ace Attorney). While gameplay of Fate/Grand Order generally revolves around battles (by selecting a team of Servants) coupled with dialogue events, this event was presented as a pure, fair-play mystery story, based solely on the dialogues between the various characters. Players were also challenged to actively participate with the mystery solving: the event took over a week (daily updates), and polls were held on the official website: players were rewarded with in-game currency if the correct answers managed to pull in the most number of votes.

As I don't play the game, it ended with me just thinking 'Oh boy, this sounded neat', but in May 2019 a second FGO Mystery event commenced within Fate/Grand Order and novelizations by Madoy himself of both the first and second event were published right after the conclusion of the second event. The first novel (based on 2018's event) has the insanely long title FGO Mystery - Hirugaeru Kogetsukan no Kokkai - Kogetsukan Satsujin Jiken ("FGO Mystery - The Confession of the Trembling Koketsukan - The Kogetsukan Murder Case", 2019), but it also carries the alternative, shorter English title of The Kogetsukan Murders. The story starts with a strange experience happening to Fate/Grand Order protagonist Fujimaru Ritsuka, as he loses consciousness one night, only to find himself waking up in a completely different body! He learns that he is now inhabiting the body of "Rikka" a friend of Juliet Violet, oldest daughter of the Violet clan. The Violet and Goldie clans are two gangster families in the United States with a long history of rivalry, but their wars have left them in a weakened state and easy targets for foreign gangs. Family heads Aaron Goldie and Adamska Violet both realize a fusion of both clans is their only chance on survival, and in order to silence the voices of protests in their respective gangs, they decide to have their eldest children marry to seal the deal. The Violet and Goldie families are now gathered in the mansion Kogetsukan on a remote island to confirm the engagement of Morris Goldie and Juliet Violet.

"Rikka" had been invited to come along as Juliet's friend, but even to Ritsuka inhabiting the body of Rikka, it's clear that Morris Goldie is not the kind of person you'd want a good friend to marry and the arranged, political marriage will absolutely ruin Juliet's life. Meanwhile Juliet seems to have accepted her fate, as she doesn't want her younger twin sister to become the 'sacrifice' in her stead.  It seems however there is another person who wants to prevent the engagement, as threatening letters were sent that warned the clans to stop the engagement, which is the reason the deal is being discussed on a remote island under the protection of three agents of the Marble Trading Company, an organization of highly respected "fixers" acting as both witnesses to the engagement and bodyguards. On the first day, a shady detective calling himself Sheringham makes his way to the island, claiming he knows of the threatening letters and that he can solve the case, but that very night, that same Sheringham is killed. It seems a murderer is roaming Kogetsukan, and that they first got rid of the nosy detective. But who will follow, and can Rikka/Ritsuka make it out alive from the island?

When I bought the novel, my main worry was of course whether I'd enjoy the story without knowing anything about Fate/Grand Order. I was fairly confident that Madoy could deliver on an entertaining mystery story, but how much would it rely on me knowing the Fate series. The first few pages were therefore slightly worrying, as they were clearly meant for someone who somewhat knows the characters. As a defense mechanism in Ritsuka's brain for suddenly inhabiting a different body, every person he meets in the Kogetsukan takes on the form of a Servant he knows within his brain. In reality, this is of course because the game uses existing character art to portray "new" characters (the people Goldie/Violet/Marble Trade Company). But an explanation that Juliet takes on the form of the Gorgon sister Stheno in Ritsuka's mind doesn't tell me much of course, as I don't know how Stheno looks like in Fate/Grand Order. Some others were more easy to imagine though. The Violet family doctor is called Dr. Hawthorne for example, who funnily enough takes on the form of the Servant Professor James Moriarty. Meanwhile, the shady detective Sheringham is definitely the spitting image of the Servant Sherlock Holmes. What's also funny is that Ritsuka occasionally returns to his own body, and there he discusses the case with both Sherlock Holmes and Professor Moriarty, who actually work together to figure things out.

Once you get past the character introductions of "X has the appearence of Y" though, I'd say the novel is fairly accessible even if you don't know Fate/Grand Order, and it's a pretty decent mystery novel on its own too. One can definitely tell it's written by Madoy, who was a member of the Kyoto University Mystery Club when in college, as the core is a classic guess-the-criminal set-up, with a proper Challenge to the Reader. While you can arrive at the identity of the murderer by simply guessing the motive in this particular story (as it's also aimed at people who usually don't read detective stories), the 'correct' way of reading this story is of course by arriving at the murderer by the process of elimination: identify what characteristics the murderer must comply too (for example, being at a certain place at a certain time, or being left-handed or something like that), and crossing off the people who don't fit that characteristic. To be honest, the elimination part of the story is on its own somewhat straightforward and not very exciting, as it mostly revolves around one single characteristic, coupled with an interpretation of a dying message which is basically 'given' to the reader. But Madoy wouldn't be Madoy if he didn't have some other tricks up his sleeve though: one point of misdirection is particularly well thought out. The trick makes excellent use of the presentation of the story and while people who do know Fate/Grand Order might be more inclined to fall for it, it still (kinda) works for non FGO-players, I think. These traps make the route to the identity of the murderer a far more entertaining trip and are nicely done. At least, in general. I do think some of the hints stood out a bit too much: some parts of the story seemed so blatantly weirdly worded at first, I actually thought it was an editing mistake in the text, rather than a hidden clue. I wonder whether Madoy intentionally made those parts stand out a bit, because the main audience were Fate/Grand Order players, and not mystery readers in general, as I have the feeling those parts could've been hidden in more subtle ways, without losing their functions as proper clues.

Depending on how much mystery fiction you read, bits and pieces of The Kogetsukan Murders will certainly feel somewhat familiar, like the motive or some of the 'traps' in the elimination process, but the manner in which these familiar elements are combined are good, and show how how an author, even with the same bricks, can still make an original building. Overall, I think Van Madoy did a good job at presenting a very classic mystery story to an audience (Fate/Grand Order player) that doesn't necessarily consists out of readers of mystery fiction, while still offering a story that is fairly complex in terms plotting.

Taken completely on its own, FGO Mystery - Hirugaeru Kogetsukan no Kokkai - Kogetsukan Satsujin Jiken is a decent mystery novel and can be enjoyed too even if you don't know Fate/Grand Order, but it definitely earns some bonus points if you are familiar with the source material and some elements of the mystery plot too work better with some knowledge. And while this was originally written to be experienced in the game, I'd say the novelizations works quite well too. While designed for a more general audience, this novel will also please regular puzzle plot readers and it's also just funny to see the Servants Sherlock Holmes and Professor Moriarty working together to solve the murders at the Kogetsukan. I have the novelization of the second event too, and will probably review that one soon too.

Original Japanese title(s): Type-Moon (原), 円居挽 『FGOミステリー 翻る虚月館の告解 虚月館殺人事件』