We're doing strange things — the neighbor's observation struck Ma En as completely accurate. People who'd never been exposed to this kind of bizarreness, who couldn't share the experience, who had no access to the information hidden inside it — they'd never be able to understand what the two of them were doing right now. Why would a body be in someone's room? Why would you carry a body into a forest and bury it? In the eyes of ordinary people, this was probably just two dangerous lunatics destroying evidence of a crime.

Ma En leaned against a nearby tree trunk and methodically re-splinted his broken little finger, rewound the bandage tight. What the neighbor was now preparing to do had, originally, been the thing Ma En had been most curious to see this entire night. After what had happened at the shrine, though — even if the body revived right in front of him and transformed into a monster — he couldn't bring himself to feel shocked. There was still some anticipation. But the monster-birth scene, compared to what had come before, now felt like dessert after an exhausting main course. Something calmer and smaller, though still worth witnessing.

He no longer doubted that the young man's body would change. The trees here were ordinary; the body was ordinary; making two ordinary things into something beyond all common sense should have been difficult to imagine — but he had directly seen a thread enter the body in that aerial instant. Unimaginable change had, in that same moment, been folded into understanding. He still couldn't explain the theory behind the monster-transformation. But he could guess at the primary cause.

The primary cause was those threads.

Without those threads, a body buried under a tree would simply decompose — nothing more. And what he and the neighbor were doing would be genuinely indistinguishable from people trying to hide a corpse. With the threads — assuming that what he'd witnessed in the aerial vision was real and objective — the threads served as the connection between a person and a tree, enabling a fundamental internal fusion and change between them. Not particularly difficult to imagine, once you knew what you were imagining.

The neighbor had not directly buried the body. He'd been drawn by some spiritual guidance and compulsion to perform the ceremony first — putting Ma En briefly into lethal danger. But that, undeniably, had been the thing that mattered.

Yes. If that sharp, unexpected, harrowing sequence of events hadn't occurred, Ma En would certainly have missed substantial intelligence. As it was, the encounter had cost him badly. And yet — looked at from another angle — wasn't this also how fortunes turned?

Finally, the neighbor jumped out of the pit and exhaled — Ma En couldn't see the specific gesture in the dark, but the tone of it was unmistakable. "It's ready."

"That's it? Just bury the body under the roots?"

"That's it." The neighbor paused, as if trying to defend what had happened before. "But the ceremony really is necessary — just burying it without the ceremony does nothing. I just... I just... in the moment, I forgot... I'm sorry. I truly thought you wouldn't be in danger."

He said this, then frowned and asked again: "What actually happened? Worshipping the Matchmaking God has never injured anyone who was just standing nearby before. Did you do something unnecessary?"

"I was just watching, and then I was like this." Ma En answered vaguely. What the neighbor called "unnecessary" was not, from Ma En's perspective, unnecessary at all. But could the neighbor understand? No — Ma En felt he needed to keep the secret. He found the irony almost funny.

He'd never liked the neighbor's secrecy. Now he'd become one himself — both of them carrying their own secrets, secrets that might seem trivial to others but were, for each of them, necessary to hold.

Fortunately, Ma En might not have liked secrecy, but he could accept it. Both the postal service and the culture of his homeland had always placed considerable importance on confidentiality.

As the saying went: when affairs are revealed prematurely, harm follows — so the wise man guards what he knows and does not let it go.

"Hm-hmm... kid, I'm starting to like you. You have something of my quality about you." The neighbor said this with unmistakable significance. Ma En noticed: the intelligent, sharp, perceptive detective seemed to have returned to that vast, ugly body.

"Before long," the neighbor said, "you'll become a keeper of secrets yourself — like me."

"I don't think that's a good thing." Ma En answered without expression.

"Is that so? I'd say the old you would have been fine with it."

"I don't intend to remain in the past. People grow."

"Yes. People grow." The neighbor seemed to have more to say, but Ma En could almost predict what was coming — and before he could, the topic shifted. "Hear that?"

"Hear what?" Ma En blinked.

"Listen. Feel it." The neighbor fixed his gaze on the tree above the buried body. "It's started growing too."

Ma En steadied himself and reached toward what was happening in front of him with his full attention. When he truly concentrated, a strange movement came up from the earth below his feet — as if the dense network of roots in the soil was stirring. He watched the tree carefully. At first, nothing visible. But after he'd been watching long enough — perhaps long enough to produce a trick of the eye — the tree seemed to be shifting. He couldn't name exactly what was changing. It was extremely subtle, extremely complex, barely reaching the surface of the bark, the kind of thing that could only be felt by sensing the whole of it rather than any part of it.

An ordinary tree. An ordinary body. An ordinary burial. Yet something extraordinary had begun.

Everything he'd been thinking came flooding back.

The threads were at work.

But what exactly were the threads? Their form and nature were unlike what he'd seen in the nightmare — but if the things in the nightmare were as distorted as the neighbor had suggested, then assuming the threads themselves were the Matchmaking God — or something the Matchmaking God produced — wasn't impossible. Perhaps the threads were the deepest foundation of the monsters who could cross the cosmos: not just spiritually connected to them, but the physical substrate of their existence.

Which would also explain why the monsters worshipped the Matchmaking God — they depended on it not just in belief but in survival. The dependence was real, physical, existential.

The relationship was not only spiritual worship. It was practical, material survival.

He felt he could now sketch a rough draft of how all these entities related to each other. Questions remained — mutual dependency versus parasitism, whether the relationship was reciprocal, whether the Matchmaking God consciously directed the monsters or was simply something the monsters had discovered and chosen to exploit — but for the purpose of resolving the Room 4 Ghost Story, not knowing those answers was no obstacle.

Because what he needed to do was not kill all the monsters — that was impossible — but remove whatever was making them surge and stir. Perhaps Matsuzaemon. Perhaps the threads themselves.

The neighbor was certain the primary cause was Matsuzaemon. As for Ma En — he now believed the threads were the primary cause.

Even Matsuzaemon — if he truly functioned the way a cult leader was said to function, directing the monsters who lived in human form across human society — was perhaps only a front, a surface manifestation, a visible placeholder for something deeper.

He believed that the neighbor and Matsuzaemon both contained those threads. The difference between them and this newly-born monster was probably not, at root, a difference in form, power, or status — but a difference in the nature of the thread within them. Which would also explain why the neighbor insisted that "Matsuzaemon cannot be killed by any human scientific method" — because the threads might simply be beyond what contemporary science could address.

Going further: the neighbor had earlier been uncertain whether "monsters who die in human form are truly dead in any real sense" — couldn't the same principle explain this?

Not just Matsuzaemon — all the monsters were in some sense deathless. Only their human forms died. And Matsuzaemon's particular thread, whatever made it special, might allow him to survive even the death of his human form.

Though these were still hypotheses. He needed to test them further before acting on them — facing a danger that genuinely couldn't be observed through normal means, he didn't think he'd have many opportunities to course-correct.

The most important piece: the threads he'd witnessed from that strange angle were real. Not a hallucination.

He'd considered reporting his findings — to his party, to his government — asking for institutional support to confront the threads directly. But in the time remaining, what kind of response could he realistically get? Even with his postal service background, predicting a favorable outcome was difficult. And if the threads truly exceeded the reach of contemporary human science, the appeal would be hopeless regardless.

How many people would invest time and energy in this — choosing to open an entirely new field of research rather than pursuing the known-but-unproven frontiers where the next discovery was already waiting?

Two months. Only two months. Humanity had near-infinite time. He had two months.

His heart beat hard. He'd been thinking many things, and the more he thought, the more the pressure of time pressed down.

In front of him, the tree showed no larger or more dramatic change. Everything happening was subtle, minute, quiet — requiring a sensitivity he wasn't sure he possessed. Or perhaps he did have it, but without the series of unknown experiences to awaken it, he would have walked past without noticing.

"How long does it take?" Ma En asked.

"Soon... ten to twenty minutes." The neighbor thought for a moment. "No more than half an hour. If the monsters performed the ceremony themselves, it would be even faster."

Ma En's gaze returned from the tree. Now that the outcome could be confirmed — the body becoming a monster was simply a predetermined result. Before that confirmation arrived, there was still something he wanted to ask.

"...I saw the threads."

"The threads?" The neighbor seemed to remember. "Right — you said that earlier. What threads?"

"When you were worshipping the Matchmaking God, some strange threads appeared from the direction of the sacred-rope rock." Ma En said. "I don't know what they are. Do you?"

"No. I've never seen anything like that... I told you before not to dig into it — but, well. Maybe it really does matter to you, so I'll say what I know." The neighbor's certainty wavered into something more hesitant. "Maybe — I say only maybe — if you really did see something, then Matsuzaemon and Miyano Akemi might also have been able to see it. But I can't. And I'm fairly certain no other monster can either. We're different. But you and Matsuzaemon—" He fixed Ma En with a gaze that was deep and strange and painful. "You're more similar to each other."

"Me and Matsuzaemon?" Ma En felt no particular surprise. When the neighbor had described the specialness of each figure earlier, Ma En had already had a premonition of something like this. "And Miyano Akemi and Hirota-san?"

The neighbor nodded. His voice became very serious: "Be careful. If you truly saw something I cannot see, Matsuzaemon will never let you reach August alive. Before he takes you, he'll take me first. Everyone else who moved into Room 4 never saw what you saw — you're the first. My instinct was right. You're my chance. You're also the one who brings my death."

"Which means you need to kill him before he kills you?" Ma En said. "You already have a plan?"

"Yes. I've thought about it for a long time. What I ended up with is a very simple plan." The neighbor finally spoke it aloud. "The more complex the plan, the harder to execute. So it has to be simple. Direct."

"Can you tell me? Straight at him — is that really it?" Ma En said plainly. "You know I can't, in front of everyone, openly help you kill a government official."

"I know, I know — you're still thinking about afterward." The neighbor's tone shaded toward displeasure. "You still don't understand, do you? If you don't let go of your hesitations, you won't survive August."

"I promised to assist you. But if your plan is too simple, there's no harm in laying it out — we can think about it together. A plan too direct and uncomplicated — will it actually work against Matsuzaemon?"

"...I see. You still don't believe me." The neighbor fixed his gaze on Ma En, and Ma En felt the familiar pressure of that stare return. "You're still doubting whether Matsuzaemon really is the central factor."

"No. I just want to hear the plan." Ma En held the gaze without flinching, resting his chin on his hand. "Because we likely only have one chance. Why won't you tell me? Is there a reason it must be kept secret?"

The neighbor seemed to have been backed into a corner by this. A silence, then: "I'll tell you. Before execution."

"You said Matsuzaemon will kill me before he kills you. And you said this is your last chance." Ma En pressed on. "You've been hiding until now — what makes you certain he'll find you?"

"Because you're beside me. As soon as he finds you, he'll find me." The neighbor said heavily. "He knows. He knows me too well. He knows I would have found you — not necessarily you specifically, but now it's you. And only you."

"...Room 4 is the bait? He's been hunting you?" Ma En almost said it before thinking. "Are you actually certain that you've been in Room 3 all this time without Matsuzaemon knowing?"

"Very certain. His attention only goes to Room 4 when someone like you appears — that's his nature." The neighbor said with confidence. "As long as he doesn't physically enter Room 3 — as long as we're not face to face — he can't sense me." He pointed to his own eyes and showed something that might have been a sly, malicious smile. "This is my ability. Something I took from Matsuzaemon. It hides me from his perception and from the monster network. He must see me with his own eyes — but he also knows: when someone who is truly chosen appears in Room 4, I will be nearby. When you saw what I couldn't see — those threads — I believe Matsuzaemon confirmed it. You are the real one Room 4 has been waiting for. The others before you were only unlucky failures."

He murmured: "He knows. He must already know. He knows it's you, and he knows I'm beside you. But he won't appear immediately — he still has preparations to make. Before he finishes his preparations, we have to kill him. We must kill him."