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この祝祭の真実は、禁忌。ポップなのにねっとり不気味な民俗学カルトホラー

失敗続きの就職浪人生・島本笑美。
原因は分かっている。彼女は物心ついた時から生きている人間とそうでないものの区別がつかないのだ。
街に溢れ返った異形のモノたちは、自分の姿が見えていると分かるや否や、笑美に纏わり付いてくる……。

ある日、ダメ元で受けた大手食品会社「モリヤ食品」の面接で、笑美はヤンと名乗る青年社長と出会う。
出会ったその瞬間から、何故か自分に惚れ込んでいるヤンに心奪われ、笑美はそのままモリヤに就職することを決める。
しかし「研修」という名のもと、ヤンに伴われて笑美が見たのは、「ケエエェェェエコオオォォオオ」と奇声をあげながら這い回る人々だった――。

一方、笑美の様子を心配した兄・陽太は、心霊案件を専門とする佐々木事務所へ相談に訪れ……。

ページを開いた瞬間、あなたももう「取り込まれて」いる。
カクヨム発の「ほねがらみ」がTwitterでバズり大反響! ネット民を恐怖の底に叩き落とした驚異の新人作家が放つ、民俗学カルトホラー!

336 pages, Paperback

First published May 21, 2021

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Rokakoen

6 books2 followers

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5 stars
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Displaying 1 - 11 of 11 reviews
Profile Image for Rebecca.
4,585 reviews69 followers
October 8, 2024
This was...unsettling. It's a dark and strange story about vulnerable people and how easily they can be fooled, a cult narrative with a supernatural edge. I suspect it won't sit well with some devout Christians, and even as someone who doesn't practice that religion, I found it uncomfortable. Interesting, yes, but not a book I'm in a hurry to revisit.
Profile Image for Lanie Brown.
402 reviews10 followers
October 16, 2025
Emi Shimamoto has spent her whole life being bullied, it's not just that she is shy and ugly she has been able to see ghosts since as long as she can remember. Emi is just weird all around and she knows this so when she moves to Tokyo to find a job, she does not have much hope, but she goes to every single interview to be turned down every single time. Until she applies at Moriya Foods, a huge corporation that not only is she certain they will never hire her but she's late for the interview as well. To her and her interviewers surprise the president of the company bursts into her interview and hires her on the spot. Emi is over the moon and calls her brother, the only person who has ever loved her, to give him the good news. But for him something is off almost immediately, Emi explains that the president's name is Jan which is not true, but he also has Emi meet him in the middle of a field in the middle of nowhere at 5am. He is certain that Emi is being taken advantage of, but she refuses to listen and after a few months his worst fears come true. Emi disappears, she refuses to answer his calls and texts and after doing his own investigation into Moriya Foods he is 100% sure she has joined a cult. Desperate to rescue her he turns to the Sasaki Agency ran by college friends Rumi and Aoyama. The two of the specialize in cases that the police can't solve: the weird and the occult. If you have a spirit making your life difficult, they will connect you with the specialist you need to remove it from your life. Rumi makes it clear from the beginning that they are not dealing with any normal cult and that they are in a race against time to save Emi, but will Rumi be enough to take down Jan?

A few months back I stumbled across Her Frankenstein by Kawashima Norikazu and to be honest I've spent months now trying to find a book that gave me that same feeling. Her Frankenstein is a terrifying tale of obsession that clearly influenced current horror manga creators including the master Junji Ito. It wasn't just that it was scary beyond all belief (yeah, I had to find some way to sneak the word scary in here) the manner in which it was written builds up the suspense in a way that by the time the whole tale has been told the rug is pulled out from under you. The ending isn't just grim it's twisted. It is one of the best examples of Japanese horror, but specifically manga, I have read to date. And yes, I know that you are all thinking what's the point here? Festival of Heresies *finally* checked every box I have been looking for since I finished Her Frankenstein. There are no monsters here other than humans and they are all gloriously disturbed.

It's going to be difficult to get through this without giving away spoilers, but I am going to try my best to make them as minimal as possible in terms of the impact on the overall story so just kind of a heads up there.

With this following a cult it leans heavily on religion (kind of, more on this later), however, that isn't immediately obvious when we are first introduced to Jan. It is established rather early on that Emi is not always able to tell the difference between a human and a spirit, possibly because of this (although Jan never states for certain) Emi is slowly introduced to the members of the cult. We watch them from afar participating in bizarre rituals and thanks to Emi's inability to tell the difference between human and dead no matter how many times it is established that they are living I still found myself questioning whether or not they were alive and to be fair once we find out what is actually happening to say that they weren't fully living wouldn't be wrong. Jan himself never comes across as human. Even after it is firmly established that he is not just a human he is barely old enough to call himself an adult he is far more demonic than any actual demon I've come across. There is something deeply wrong with him, no matter how many times the characters say that he is a calming presence every time he appeared on the pages, I got goosebumps. It's not just his obsessive behavior towards Emi, which is itself sick, it's the way he acts, no one is that nice that doesn't have ulterior motives. So for the vast majority of this book even after it is firmly established that Emi has ended up in the clutches of this cult it still feels supernatural like we are going to find out that Jan is possessed or hell the whole entire cult is. It just felt like I was waiting for a jump scare that never came. Which trust me wasn't a bad thing, this story was twisted enough without giving me a heart attack too thank you very much.

Per usual the characters were my biggest draw. By the end of the book we discover that Rumi, Emi, and Jan all endured years of truly inhuman abuse as children, all three of them discover that they have some sort of supernatural powers that allow them to see or do things that most humans cannot, they are essentially the same person in a lot of ways. What makes them each different though is how the three of them deal with their trauma.

Emi may be the most tragic of all three of them. Emi has no self-esteem to speak of thanks to the abuse she endures almost her entire life; she believes that she is a horrible person because of her ability to see ghosts and so as she ages, she becomes more withdrawn from society and really from herself. When she meets Jan who seems to not just love her for who she is but in a manner that appears to be significantly healthier than what she has experienced to date she is sunk. Jan becomes basically a god in her eyes, even though there is absolutely zero way for her to not have realized that the bizarre rituals that he is forcing herself and other members to participate in are far from right. She is one of those characters that society failed at every turn, had just one person stepped up and did something about what they had to know what was happening to her as a child her life could have been significantly different. Hell, a lot of people's lives could have been significantly different. You can't help but to be angry for her. However, as the story goes on and definitely towards the end that anger does turn a bit to apathy. It becomes fairly obvious that not only does she know that what she is participated in is extremely wrong as the entire story is told in the epilogue I realized that as the reader we barely see the tip of the iceberg in terms of the just how much damage Jan really caused and while Emi may have no directly participated she would have had to know what was happening. And maybe as I think about it it's not apathy but a feeling of waste, while Emi did not have control of much of her life due to the abuse she lived with, she chooses to waste it after meeting Jan and when put into that perspective Rumi's decisions at the end of the book make much more sense.

Jan, I believe could be seen in the same light and yet as I said earlier there is something wrong with him, even when we start diving into his past and we meet his younger self this feeling doesn't go away, actually it probably intensifies as there is something far more sinister when a child is creepy as all hell. He just seems broken and when he does finally explain how the cult he heads comes into existence it just made my revulsion of him so much worse. Since he was able to leave the cult he grew up in (same and yet not the same cult he now heads) and attend regular school as child he is able to see firsthand that there is something very wrong with how he is being raised, but not just that with how the adults interact with each other. At this point he really takes it upon himself to "fix" what he sees is wrong, but instead of say going to an adult outside of the cult, he takes to studying a multitude of religions and incorporates many of their practices (including human and animal sacrifice) into the existing cult. Now, this cult is all sorts of messed up, Jan has the members participate in not just these sacrifices but some downright bizarre rituals, but that's not what makes Jan terrifying, it's that his power allows him to control people. Cults are at their core about control; cult leaders take away their members' agency and their support networks so in the end the leader is the only person the members have to rely on. Most cult leaders have to use regular old human charisma to do this, Jan does not. All he has to do is utter a single phrase within a person's vicinity and he not only has them under his control he can watch them from basically anywhere. Cults in themselves are terrifying for their ability to coerce people into doing things that they simply wouldn't in only other circumstances, having a cult leader that doesn't even have to do that ramps up the terror significantly. However, it's not just this power that makes Jan such a powerful adversary it's how he twists the religions he studies. There is at one point towards the end where it is clear that his new church is based on a very warped version of Christianity but it's more than that it doesn't feel like there is any clear doctrine it's like he's taken created a casserole of the absolutely worst parts of multiple religions with no real rhyme or reason to it. Both Aoyama and Rumi point out more than once that they can't make sense of where certain Shinto and Buddhist beliefs fit into his belief system and they do brush this off in the end but I think it's important because it shows that it's just madness. There isn't a reason, not that I could find other than Jan wanted it there. And yet with all of that there is a certain level of empathy you have to feel for him. As we go through his childhood he clearly recognizes behaviors that are wrong among his "family" (the other cult members) and moves to change these, but I think what truly finally breaks him is at some point he realizes that everything is wrong. That it's not that other people are wrong because they don't live the way his family does it's that his family is wrong, this realization causes him to snap. He creates his new religion as not just a justification, but I believe a psychological barrier to keep him from facing what he knew was abusive behavior, what he knew was a twisting of Christianity to fit someone's twisted worldview. So even though he creeped me out the entire book I still felt for him and can see why the other characters (minus Aoyama) felt for him as well.

Finally, character wise, we have Rumi. When I finally read Rumi's backstory I was absolutely dumbfounded, there was just nothing in her character up to that point that suggested that she had such a horrible childhood. While she most certainly comes across as extremely intelligent making her intimidating at no point did, I think such violence existed within her. However, I think this is probably the most important disclosure of the book; Rumi's existence is just as bad as Emi and Jan's and yet she has turned hers into something akin to a positive. Rumi proves that we are in charge of our own decisions but moreover that we can choose to allow trauma to control you or you can choose to use that trauma to fight back. I loved her.

The other thing that I found interesting about this is how ingrained religion seems to be in the story when it really isn't. Yes, it is does seem to be Jan's motivation but it's not, Jan's trauma is. Jan isn't religious or faithful he's just a broken child with the ability to get others to do whatever he wants. Thanks to that ability Emi is the only person (maybe the real Moriya as well) that is somewhat motivated by his religious nonsense. It's genuinely the best way to tell a story about a cult, because no matter how many cult stories you dive into the leaders are never actually motivated by religion, they are motivated by a need to control people. You can definitely see this difference here when you compare Aoyama (whom I haven't talked about but did thoroughly enjoy) and Jan. Aoyama is a true believer, the way he sees his faith is how all faithful should see it. He deep dives into how people use it as a crutch and once their current crutch breaks they just buy a new one (yes I used the term buy on purpose), thinking that it must be the crutch not themselves. Aoyama's views on religion and faith are just as interesting as everything else happening in this book. Maybe more so. Especially when placed against Jan's the difference in their faith is stark.

Finally, the way this story unfolds is what made this such a phenomenal read. This is a horror story make no mistake about that but as we go through it becomes less of the supernatural horror it originally appears to be and more of a "If given the choice between a monster and a human I'm picking the monster 100% of the time" story. No matter how grotesque this entity is that centers around Jan's twisted faith (and omg she is terrifying) she's still not as bad as the humans. The humans that cause Emi, Jan, and Rumi's traumas are depraved they are the true monsters of this story and by the end of it you really feel like there was no justice done at all.

Highly recommend this one for anyone that enjoys a good psychological horror, but keep in mind that Rokakoen hits pretty every trigger warning imaginable. And to put this in perspective they even hit my fear of frogs and my even worse and extremely specific fear of dead frogs (yeah, weird I know) so not for the faint of heart on really any level. But omg is it so worth the read, like I said earlier just Aoyama's musings on religion vs faith alone make it worth the read.

Profile Image for Tyas.
Author 39 books93 followers
May 20, 2025
To be honest, I picked this one up because of the cover, which truly caught my eye. As for the blurb, I read it a bit and just thought "Oh, another one about a supernatural investigation agency... This one's probably about a cult and some youkais". As I like to read about such stuff, I went and bought the book. After finishing chapter 1, my honest thought was "What the fuck is this?" I couldn't make any sense of what's going on. I couldn't recognise any Japanese traditional belief or superstition (which I had assumed would be there) involved in all the goings-on in the opening chapter. But I was strangely attracted to the story and completed reading it in two days.

The story was— OK, I am trying not to spoil it because to me it's something that you need to experience yourself. I approached the book thinking that it's something close to the likes of Takatsuki Akira or Hell is Dark with No Flowers, but... no. Festival of Heresies is much darker, much creepier, more revolting, more uncomfortable. It's one fucked up thing after another fucked up thing. The POV changes so often, sometimes in the third-person, sometimes in the first-person of different characters. Narrations of "real-world" happenings alternate with visions/dreams. The book seems to take delight in confusing the readers right to the very end. I have never experienced what people call "a bad trip", but maybe this book feels like one, a satisfying one, if that makes sense. Not everything got a clean-cut explanation? Yes, but to me that's part of this book's dark charm.

And among all the insanity and the impurities, Aoyama—oh, Aoyama!—remains the cinnamon roll that he is. May he always be safe through all his twisted adventures and investigations with his senpai.
Profile Image for J-Lynn.
1,510 reviews4 followers
September 17, 2025
What the f*ck did I just read? Seriously, it’s gross.

As the story progresses, you learn more about the characters’ backstories and it is wild. Also, every single character (except Aoyama) is awful and disgusting! (ノ◕ヮ◕)ノ*:・゚✧ Aoyama is the best and deserves better, in my opinion. Rumi is complicated….. love Rumi, but wow!

Whenever I would sit down to eat lunch, I would pick this book up and IMMEDIATELY start reading a gross scene….. three meals were ruined cause of this. THREE! Regardless, I’m going to continue reading this series despite how absolutely disgusting this book was. This book had me hooked in a bad way. I should not have enjoyed this as much as I did….
Profile Image for Mima.
26 reviews
April 1, 2025
This was uncomfortable to read. I did not expect it would've many trigger warnings when I first picked up this book, such as grooming, incest, child abuse, animal abuse, religious trauma etc. I thought it would just be a light read about typical paranormal squad, so I guess it's part of my fault too. It's basically a story about the rising of a cult, with a mix of Christianity beliefs and supernatural. I'm not a Christian myself, so I don't really relate with the religious theme this book has. Overall, it has interesting concept, but I don't think I would ever re-read this, tbh.
Profile Image for nekoneko.
136 reviews4 followers
September 8, 2025
Holy smokes \(˚☐˚”)/

I am not a horror reader but from the description I didn't think it'd be too bad

I was wrong

I will not be sleeping tonight (ó﹏ò。)

(I only give it four stars because sometimes the breaks in narration were confusing.)
Profile Image for V.
2 reviews
February 12, 2026
Probably one of, if not the most fucked up book I've read. 10/10
Profile Image for Emi.
1,007 reviews41 followers
February 2, 2023
ホラー小説は普段あまり読まないからなんか新鮮(というかホラーというジャンルがいまいちよく分かってない)。
特殊な能力を持った人物が結構出てきて、異能力バトル?領域展開?的な場面もあって、怖さを感じるよりも普通にエンタメとして楽しんだ。
Profile Image for Asuka.
324 reviews
March 5, 2023
読みやすいし、青木くんは良い人で好印象。怖いとは思わないけど、楽しめます。ただ最後の意味がわからない。

Easy and entertaining read. Aoki is quite likeable. But I didn’t get what it meant at the very end of the story. Also, not really scary.
Displaying 1 - 11 of 11 reviews