Do You Know Oyashiro-Sama?I recently completed a short campaign of Monster of the Week. It… went places, but I’ll discuss that in a later post.

The following mystery is not one I wrote for that campaign. It’s something I threw together after I was shown a message board thread that discussed how to build the Groundhog Day time loop in the series Higurashi: When They Cry (Higurashi no Naku Koro ni) as a Dresden Files Fate powerset. After some thinking it occurred to me that pieces of the story could be easily developed into Monster of the Week Mystery fodder.

Please note that the following does contain spoilers for Higurashi: When They Cry. It’s a complete Mystery, so there’s no way to hide spoilers.

Hinamizawa Syndrome: A Monster of the Week Mystery

On Adapting Higurashi: When They Cry into a Roleplaying Game

The basics of Higurashi translate well into Monster of the Week: there’s a small town with some big secrets, both supernatural and mundane conspiracies at play, a cast of strange locals and major stakes. If the Hunters fail, they’ll wipe the whole community off the map. It works as a decent bottle mystery.

I wouldn’t try to adapt the plot too directly; a lot of the driving force of the story is based around failure, decoy protagonists and distrust, none of which are really great in large doses at a gaming table. The time loop is hard to put into play without the players knowing what’s going on. Further, when you players derail things, remember that you don’t need to keep the alignments, the events and characterizations to the letter of what was in the original story. I’ve laid some of them out very loosely myself.

There’s two ways I can see this mystery used in a game:

1) In a currently running campaign, the Hunters are outsiders come to the community, get caught up in the mystery and resolve it on their own. This would be like Mamoru Akasaka in Time Killing Arc, but set in whatever your current time is rather than four years in the past.

2) If the game is meant to be a one-shot and if you accept that this is an alternate world that wasn’t shown in the series, you could let the players play characters from the show. Most of them would fit into the playbooks with some wrangling. Of the top of my head, I would put Keiichi as the Chosen, Mion as the Mundane, Rena as the Expert or the Flake, Rika as the Initiate or the Spooky and Shion and Satoko as slightly modified versions of the Monstrous (to reflect the personality disorder and L5 Hinamizawa Syndrome, respectively).

For people who just want to grab finished characters and go, you can find stat blocks for the main characters over here.

The Concept

The small town of Hinamizawa has been plagued with a series of deaths and disappearances. They have occurred on the same day over the last four years: the third Monday in June, the day after a local festival. The locals claim that an angry local god is behind these events and the deaths are the result of the god’s anger for a construction project that almost destroyed the village several years ago.

In addition, many people in the town suffer from Hinamizawa Syndrome, a mental illness caused by a local parasite. The illness triggers off of stress and anxiety and causes the sufferer to have disturbing hallucinations until they violently lash out. The illness eventually ends with the victim committing suicide.

The original setting of the story is rural Japan. You could make the story fit in any rural setting if you file off the serial numbers and change the names and some of the setting details. Oyashiro could become an old pagan god or an urban legend rather than a shrine god if you want to set the story elsewhere, for example

Potential Hooks

– If the Hunters are being proactive about supernatural threats, they may have pieced together the the unusual pattern in deaths before anyone else has investigated.

– The pattern in the deaths may have been noticed by someone the Hunters know, such as a fan of the occult or a tabloid writer, and passed along. Ask the Hunters who this person could be and what his or her history with the party is.

– Members of the village who have moved away tend to engage in unusual practices, such as hanging talismans. This is meant to protect a person against the wrath of Oyashrio. Ask the Hunters who noticed these first, how they feel about them and how this lead to them coming to the village.

– In the a one shot, the Hunters could be locals who decide to try to put a stop to the deaths and disappearances themselves. Their relationships should be decided using History.

Countdown Clock

Day: A strange murder occurs in the town of Hinamizawa. Miyo decides to use this as a cover to put the final phase of her research into place.  

Hinamizawa should be on the Hunters’ radar before the start of the story, but this is what leads them to the town a few days before the festival. The murder seems ritualistic in nature – the victim died from being disemboweled, but was clearly tortured for quite a while before dying. Confusingly, despite the nature of the death, the timing of the murder doesn’t follow the pattern of the deaths in years past. There’s also no disappearance to go along with it.

Points to consider:

– Who was this person? What did this person do? Who wanted to this person dead? You have a few options here. The person could have angered the Three Great Houses, a group that controls the politics of Hinamizawa. It’s possible that Miyo performed the murder, given her knowledge of the occult and the village’s history. Or the murder could have either a supernatural origin or another more mundane one.

– How are the local villagers reacting? If the person was causing trouble in the community, some of the locals might claim that the death was Oyashiro’s will and think nothing more of it. Others may point fingers towards the Three Great Houses. Miyo, if encountered at this stage, will claim the murder has occult ties to Oyashiro’s crazed followers.

Shadows: The Watanagashi Festival is held. The Saiguden is broken into by Miyo.  

The Watanagashi Festival occurs, giving the Hunters a chance to meet bystanders they haven’t encountered before. Of note is Rika Furude, a young girl with a premonition that she will be one of the victims after the festival. These visions of the future don’t tell her how she’ll die or who the person behind it is, so she feels powerless to stop it. Rika will gravitate towards anyone with some knowledge of the supernatural for protection. The Hunters happen to be in the right place at the right time.

If the Hunters are searching for something amiss, they will discover Miyo and Jirou trying to break into the Saiguden. If spotted, Miyo will spin this her being curious and will try to get the Hunters to join her in the break in, all while playfully discussing the rumours about the Saiguden and her theories on Hinamizawa Syndrome, a local illness that drives people mad until they kill themselves.

Points to consider:

– If the village’s status quo has been lost on the Hunters thus far, now is a good time to establish it. The festival is closely tied to the mysterious murders and deaths and it’s likely the locals will be discussing it.

– Why is Miyo breaking into the Saiguden? Is she looking for ritual tools for a reason? Or is she just bored and curious?

Dusk: It’s the morning after the festival. Miyo is reported dead and Jirou is either reported dead or missing.

Miyo, or, rather, the charred corpse of a person who appears to be Miyo has been found in the forest outside of town. The time of death was determined to be several hours before the festival. The news of the death(s) and/or disappearance will be relayed to the Hunters by Ooishi. Ooishi is another outsider searching for the person behind the murders for personal reasons. He suspects that the village leaders are behind the crimes.

Points to consider:

– It should be clear that the timeline given by Ooishi doesn’t match up. The Hunters saw Miyo on the night of the festival long after her recorded time of death. Do they have proof of the encounter the night before?

– Ooishi will try to broker a deal to get both him and the Hunters investigating the murders together. It’s a shady deal and should be clear that Ooishi is doing this for his own gain. He won’t trust Rika because of her ties to the village leadership, causing complications if she has aligned with the party.

– The original storyline has Jirou found death the morning after the festival, having committed suicide in an unusually gruesome manner. If the Keeper wants to keep him alive longer, have him be missing instead.

– However, if two deaths are reported, consider that this is breaking the pattern of years past. If two people have died, does this mean that two people need to go missing?

Sunset: Hinamizawa is Sealed off From the Outside World.

Miyo faked her death to be free to complete her research on Hinamizawa Syndrome. Her research has lead to her theorizing that stress and anxiety trigger powerful reactions in people with the illness. She tries to get as big a reaction out of the community as possible by having her military backup quarantine the community.

In the chaos that follows, Miyo will take the opportunity to kill off anyone who’s discovered that she’s not dead and anyone who’s seen or heard too much of her research through her babbling.

Points to consider:

– What’s the cover story for locking the village down? Or is Miyo so prideful that she reveals herself and her claims about Hinamizawa Syndrome directly?

– This is your chance to throw off the status quo. Threaten bystanders who are friends with the Hunters. Have the villagers become aggressively distrustful of the Hunters; everything has gotten to hell since they arrived. There’s nowhere safe for the party to hide and, with the village locked down, no where to go. Miyo knows this.

– If Miyo is aware of the supernatural nature of some of the Hunters, Miyo might make them a side project. She could put attentional pressure on the party to see how their Hinamizawa Syndrome infections react to the stress.

Nightfall: Rika is kidnapped and murder by Miyo.

The community is on edge and falling apart under quarantine. Rika attempts to escape, only to be captured by Miyo’s forces. Miyo murders Rika in the name of completing her research. Her theory is that the Great Houses play a role in balancing the Hinamizawa Syndrome within the village and that killing off a bloodline will cause the illness to spiral out of control.

Midnight: The Great Hinamizawa Disaster Happens.

With the regulator of Hinamizawa Syndrome dead, Miyo orders that the rest of the population of the village be wiped before the Syndrome fully activates in everyone. The military gases the community. If the Hunters are still in the village, there’s a tiny window of opportunity for them to escape. If they don’t attempt an escape, then they’re killed along with everyone else.

The cover story for the media is that a cloud of volcanic gas burst up through the swamp, instantly killing everyone in the village.

The Monster

I’ve stated out two potential monsters to be used, depending on which way the Keeper wants the story to go. Miyo Takano is the antagonist in the original story, a researcher studying Hinamizawa Syndrome. Oyashiro is the story’s decoy antagonist, the local shrine’s protector god. Instead of working alone, perhaps Miyo has made a pact with Oyashiro for power. Or maybe the deaths are all supernatural in nature and Miyo’s research is a red herring.  For a more canon-correct interpretation of Oyashiro, look for Hanyuu in the Bystanders section.

Miyo Takano

Description: Miyo is a woman in her mid 30s. While not at working at the local medical clinic as a nurse, she keeps a very casual appearance. She has mid-length blonde hair, brown eyes and gives the impression of being overwhelmingly subdued or even sleepy most of the time. However, this is all a carefully constructed front.

Motivation: Sorcerer (to usurp unnatural power)

Miyo believes that godhood and power can be obtained by being notable in enough to be recorded in history books. She intends on doing this by proving the existence of Hinamizawa Syndrome and completing her adopted father’s research. She’s been behind most of the murders linked to the festival over the last four years; the deaths and disappearances have either tied directly to her research or were to eliminate people standing in her way.

In addition to this, she is fascinated by Hinamizawa’s history with the occult and happily spreads rumours about it. It serves as a good cover for her crimes. Her research is being funded by an outside party who is less interested in Miyo’s hobbies and more invested in the bioweapon applications of Hinamizawa Syndrome.

Powers: Infect with H-170 (see Custom Moves)

Weakness: Miyo is mortal. A fatal wound will kill her.

Attacks: M1911 pistol (2-harm close reload loud)

Armour: 1-armor

Harm capacity: 10

Custom Move: Infect with H-170
H-170 is a weaponized version of Hinamizawa Syndrome, the product of Miyo’s research so far. The Hunter is infected when Miyo injects them with the drug. The Keeper can present a distorted view on the current situation and ask a Hunter to do something terrible in accordance to with the following tags:

– Violence

– Self-destruction

– Hallucinations

When asked, the Hunter rolls +Cool. On a 10+, the suggestions have no effect. The Hunter takes +1 forward, regaining enough self control to use the drug to their advantage. On a 7-9, the Hunter has the option to act on the suggestion or not. If the Hunter acts on the suggestion, they mark experience. If they Hunter doesn’t act, they get take +1 forward, exactly like in the 10+. If the Hunter fails, they’re at the mercy of whatever twisted urges overwhelm them.


Description: Despite common belief, Oyashiro is a female god. In her humanoid form, she looks to be in her early 30s and has long, light purple hair, deep purple eyes and a pair of black horns on her head.

Motivation: Executioner (to punish the guilty)

Several hundred years ago, Oyashiro was a demon who sacrificed herself in other to bring her tribe and the human village together as one people. This set into motion the status quo up  until four years ago, when a dam construction project threatened the village. The dam project was eventually halted, but Oyashiro’s wrath against those who would try to destroy her village continues.

Powers: Alter the flow of time, freeze the flow of time, flight, telekinesis, intangibility.

Weakness: Bound to Hinamizawa and cannot stray far from the village. Her powers are connected to how many people worship her; if she loses all of her followers, she ceases to exist.

Attacks: Sacred sword – “Onigari-no-Ryuou” (3-harm hand magic messy)

Armour: 2-armor

Harm capacity: 12


Name: The Yamainu/The Wild Dogs (swarm/group)

Description: The Yamainu are counterintelligence military force working with Miyo Takano’s backers. They can be spotted around the village wearing gray uniforms and travelling in unmarked white cargo vans.

Motivation: Scout (to stalk, watch, and report)

The Yamainu’s main priorities are to project Miyo’s research team and Rika, believed to be the regulator of Hinamizawa Syndrome. They excell in covert ops work but are weaker in direct combat. As the Countdown Clock progresses, Miyo bribes the Yamainu to help her quarantine the village and fake the volcanic gas leak.

Powers: None.

Weaknesses: None, but are mortal humans.

Attacks:  Nightstick (2-harm hand), Silenced 9mm (3-harm close), Assault rifle (4-harm close automatic loud)

Armour: 1

Harm Capacity: 9 harm will cause the group to disperse.


Jirou Tomitake

Motivation: Innocent (to do the right thing)

Description: Tomitake claims to be a freelance photographer in his late thirties who visits the village to see his “girlfriend”, Miyo. He’s actually an auditor supervising Miyo’s research project and becoming increasingly concerned about Miyo’s ethics.

Ooishi Kuraudo

Motivation: Busybody (to interfere in other people’s plans)

Description: Ooishi is a police detective in his early fifties. He lives in the nearby city of Okinomiya. Ooishi has been researching the murders over the past four years; his close friend was a victim four years ago. He suspects that the whole village is behind the murders.

Irie Kyousuke

Motivation: Official (to be suspicious)

Description: Irie is a man in his early thirties and is the village’s local doctor. He;s cheerful on the outside but has a shady past within the medical community. He moved to the community to help Miyo with her research, but this isn’t publically known.


Motivation: Witness (to reveal information)

Description: Hanyuu is the true form of the infamous Oyashiro of rumour and legend. Her humanoid form is that of a young girl, about eleven, with light purple hair, deep purple eyes and a pair of black horns on her head. She’s a soft spoken and polite god who’s crushed by the evil acts people perform in her name. Despite this, she’s often found lingering in the disturbing Saiguden.

The Three Great Houses

The community of Hinamizawa has been run by three families since its founding: The Kimiyoshi family, the official leaders of the village; the Sonozaki family, the actual power in control of the village; and the Furude family, the caretakers of Hinamizawa’s shrine and the centre of the village’s spiritual community.

Rika Furude

Motivation: Victim (to put themselves in danger)

Description: Rika is an eleven year old girl. While young, she’s has been head of the Furude family since her parents killed several years ago. She’s responsible for the upkeep of the Furude Shrine and the performance of rituals at the shrine. Recently, she’s been receiving premonitions that she will be a victim of the deaths and disappearances this year, but hasn’t found anyone who believes her. Miyo’s research claims she’s the regulator of Hinamizawa Syndrome.

Kiichirou Kimiyoshi

Motivation: Skeptic (to deny supernatural explanations)

Description: An elderly man in his sixties. Kiichirou is the village chief, although any power he has is purely for show; Oryou wields the actual power within the village. He believes that Oryou Sonozaki orchestrated the murders over the last four years in order to eliminate enemies of the village.

Oryou Sonozaki

Motivation: Official (to be suspicious)

Description: An elderly woman, around seventies years old. Oryou is the harsh and blunt leader of the Sonozaki family, the Great House that’s believed to have the strongest demonic blood ties. Her public face is one of keeping the status quo. However, she’s becoming increasingly concerned about the village’s future if things remain stagnant and is privately welcoming of outsiders.



Description: Hinamizawa is a small, rural village of about 2000 people. It’s located in dense forest, making it hard to reach the community isolated. A lot of the buildings and structures are incredibly dated, making the village seem lost in time.

Motivation: Prison (to constrain and prevent exit)

Hinamizawa is both unsettling and yet welcoming. Many locals are distrusting of the outside world, but are genuinely nice people once their trust is gained. This front of distrust stems from worship of the local god, Oyashiro, who instructed the local population to never even think about moving away from the village and to keep outsiders away. The practices were put into place to try to control the spread of Hinamizawa Syndrome, a mental illness caused by a parasite found only in Hinamizawa. The Three Great Houses are aware of this and try to hide the full truth from the rest of the village.

Custom Move: Hinamizawa Syndrome

Being around Hinamizawa for any length of time places the Hunters at risk of contracting Hinamizawa Syndrome. The Keeper can present a distorted view on what’s happening and ask a Hunter to do something terrible in accordance to with the following tags:

– Hallucinations

– Mood swings

– Paranoia

When asked, the Hunter rolls +Cool. On a 10+, the suggestions have no effect. The Hunter takes +1 forward for assisting others with Hinamizawa Syndrome, having gained some understanding on the infection. On a 7-9, the Hunter has the option to act on the suggestion or not. If the Hunter acts on the suggestion, they mark experience. If they Hunter doesn’t act, they get takes +1 forward for assisting others, exactly like in the 10+. If the Hunter fails, they’re at the mercy of whatever bizarre urges overwhelm them.

Aside: The symptoms of Hinamizawa Syndrome will fade if the Hunter has been outside of Hinamizawa for any length of time. It will not affect ongoing campaigns after this Mystery.

Onigafuchi Swamp

Description: Onigafuchi Swamp is, despite the name, a long, narrow lake that runs along the side of Himamizawa.

Motivation: Deathtrap (to harm intruders)

There are reports of a magma reservoir located under Onigafuchi Swamp. If the reservoir breaks the surface of the lake, it could release a volcanic gas cloud that threatens the community.

The Dump

Description: On the far reaches of the village is a pit where locals illegally dump garbage.

Motivation: Hub (to reveal information)

While the villagers might not be forthcoming about the deaths and disappearances over the last four years, their garbage doesn’t lie. Newspapers detailing the events can be found in the dump with a little digging.

The Saiguden

Description: A sacred tool shed located behind the Furude Shrine. The shed is always locked and breaking into it is taboo among the locals, but there are rumours about what it contains…

Motivation: Wilds (to contain hidden things)

The inside of the Saiguden looks like a torture chamber, with various horrible looking implements and tools. In the centre of the chamber is a large statue of Oyashiro. Records and information stored in the Saiguden reveals that the “Watanagashi Festival”, referred to as the “Cotton-Drifting Festival” by the locals, can also be translated as “Intestines-Drifting Festival”.

 The Furude Shrine

Description: A shrine dedicated to Oyashiro and mantained by the Furude family for as long as the village has existed. Oyashiro may hold huge sway over the village, but the shrine is very modest and simple.

Motivation: Lab (to create weirdness)

The shrine is home to all sorts of weirdness. The Watanagashi Festival’s strange rituals, which involve ripping cotton out of a mattress, are held in the shrine. Behind the shrine is the Saiguden, a shed that only members of the Furude family can enter, least a trespasser come to the attention of Oyashiro. It’s rumored that Oyashiro itself can be summoned at the shrine if the proper offering is made.

Irie Clinic

Description: The Irie Clinic is a small medical centre that serves Hinamizawa and the surrounding area. It’s more elaborate than a simple doctor’s office as it also serves as a rural hospital. The building is well-kept and welcoming enough for a clinic, but…

Motivation: Hellgate (to create evil)

In the basement of the clinic is where Miyo and Irie have set up their research lab. The basement is protected with a top-of-the-line security system. Once past security, there are operating rooms, quarantined patients and other various experiments tied to Miyo’s research.   

The Watanagashi Festival Grounds

Description: The festival is the village’s biggest public event. Booths and vendors are set up around the Furude Shrine for the one night celebration. The event ends with a bizarre ritual where old, used cotton from the village is ripped out of a futon mattress by the local priestess. The cotton is handed to festival goers, who then place the cotton into the nearby river and let float away. It should be noted that the name for the festival commonly translates to “Cotton-Drifting Festival”.

Motivation: Crossroads (to bring people, and things, together)

The Watanagashi Festival has become a rallying point for locals since the dam construction project threatened to destroy the village. The festival is held in honor of Oyashiro, who is believed to have used its powers to stop the project and save the village. The event has been the cause of some trepidation as well due to the mysterious deaths and disappearances that follow the day after.

The Sonozaki Compound

Description: The Sonozaki family is one of the Three Great Houses and their home reflects that. They have a large, traditional looking house by the river’s edge. The property is surrounded by high walls and is gated in the front.

Motivation: Deathtrap (to harm intruders)

Hidden away in the Sonozaki property is a secret torture chamber, a dungeon, and an extremely deep well. The implements found here are not unlike the ones found in the Saiguden.

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