The mid-winter wind carried fine shards of ice, lashing against the desolate mountains surrounding Tokyo. The air was so cold it stung the lungs with every breath.
Tatsuya wrapped his thick haori tighter. Through a cluster of frozen vines, he finally saw the entrance to the cave described in his mission—a black void like a jagged wound in the earth.
"A cave in the middle of nowhere," Tatsuya muttered, tightening his gloves. Thanks to his Breathing Style, he didn't feel the chill. "Usually, these stories feature a man-eating demon. This time, it's a Demon Slayer like me."
Unlike previous missions, there was no Wisteria House nearby. He patted his bulging pack, full of hard rations and water. "Good thing I planned ahead. This place is all rocks and snow."
He stepped inside.
The cave wasn't deep. A flickering fire soon dispelled the cold of the entrance, illuminating the figure of a man sitting cross-legged. He looked to be in his early thirties, with long golden hair that looked like leaping flames, tipped with bright orange-red.
He had thick, striking eyebrows and radiated energy even with his eyes closed. When he opened them, they were bright, sharp, and filled with a fiery vitality—reminding Tatsuya of an owl that could see through the dark.
The man stood up nimbly with a hearty smile. "Oh! It seems Slayer Izumo Tatsuya has arrived! Good work traveling in this weather! I am the current Flame Hashira, Shinjuro Rengoku!"
"He doesn't have the arrogance I expected from a Hashira. Seems easy to talk to."
Tatsuya bowed. "Lord Flame Hashira, I am Izumo Tatsuya." He was struck by the man's aura—it felt like a burning, stable furnace. His breath was deep, his stance flawless. Just standing there, he felt terrifyingly strong.
"Good! Now everyone is here!" Shinjuro nodded.
"Everyone?" Tatsuya blinked, looking around the small cave. "Lord Hashira, it's just the two of us? I thought a mission involving surveillance or evacuation would require a squad…"
"Hm! A good question!" Shinjuro slapped Tatsuya's shoulder with enough force to make him feel like he'd been hit by a hammer. His expression turned serious. "This mission is tricky."
"We've had reports of traveling merchants vanishing in this area. We initially suspected bandits, but all tracks lead to one place—an ancient estate over the mountain belonging to the Iguro family."
He paused, his voice dropping. "Worse, we sent three experienced Kakushi specialists to infiltrate and gather intel. None of them returned."
Tatsuya's heart sank. If the Kakushi specialists were lost, the danger level was extreme.
"The estate is massive, with complex staff and many servants," Shinjuro continued, his brow furrowing. "If a demon is truly entrenched there, we don't know the relationship. Are the owners being coerced, or are they in league with it?"
"There are likely many innocent servants inside. My duty is to slay the demon, but charging in blindly could lead to civilian casualties or allow the demon to use hostages to escape. I've heard of your exceptional perception and reconnaissance skills from your previous missions. That is exactly what we need!"
"I need you to infiltrate that estate. Find the demon's exact location, assess the situation, and if possible, find our missing comrades. Once you lock onto the target and signal me, I will arrive in an instant to finish it. I leave the task of finding the truth in the darkness to you!"
Shinjuro handed Tatsuya a small, heavy signal flare. "Use this, Slayer Tatsuya! Once the target is confirmed, fire it! I will arrive like a torrent of fire!"
"Easier said than done. Infiltration is a first for me."
Leaving the Flame Hashira behind, Tatsuya suppressed his presence, moving like a night owl through the forest. Under the sparse moonlight, the ancient estate loomed in the valley.
It was a classic samurai-style manor over two hundred years old, with Meiji-era glass windows forced into a heavy Edo-period frame. The high dirt walls were covered in dark moss and topped with heavy tiles. Small guard towers were spaced along the perimeter.
It was massive, capable of housing hundreds. In the center stood a prominent three-story structure—the lord's residence.
The layout was a maze of rooftops. In the silence, Tatsuya could hear the rhythmic clack of wooden sandals from patrolling guards.
"This isn't a house; it's a fortress," Tatsuya thought. "Guards and sentries everywhere."
He activated Silent Listening. Vroom— The world of sound was amplified. Wind and insects were filtered out; footsteps, breathing, and even the distant clatter of dishes in the kitchen reached his ears.
"Found it!"
At the northwest corner, a section of the wall was shrouded by a massive pine tree. It was a blind spot between two guard towers. Tatsuya scaled the wall like a gecko, moving silently and using only his fingertips for leverage. He dropped into the shadows of the inner bushes like a weightless feather.
"I'm in."
He crouched low. The pressure inside was even stronger. The courtyards were a complex arrangement of rock gardens and corridors—elegant, but full of blind spots. He heard two guards approaching from the right; further away, behind a moon gate, he heard the faint, rhythmic breathing of a hidden sentry. Deeper in, near the central tower, he heard the sounds of music and laughter—a bizarre contrast to the cold guard outside.
"The patrols are easy; the hidden sentries are the problem."
Tatsuya moved through the rock gardens, avoiding the main paths. He reached the servants' quarters, where the chaotic mix of scents and sounds actually provided better cover. He found a narrow service passage leading toward the main kitchen, smelling of food scraps and wastewater.
He slipped inside, timing his movements to avoid several exhausted servants pushing empty carts. The passage led to the massive kitchen area. Tatsuya moved like a shadow along the storage room walls. Above, he found a narrow ventilation crawlspace.
"I'll take the high road."
He spent the next two hours scanning the rooms below.
"There are about a hundred and fifty people here," he calculated. "A hundred of them have heavy breathing and rough clothing sounds—laborers, servants, and armed guards."
What truly caught his attention were the other fifty people. Their breathing, gait, and even the sound of their clothes were entirely different. All fifty of them, without exception, were women.
Their footsteps were light and casual. They wore expensive, rustling silk. More notably, they were draped in heavy jewelry. Every movement—even the rise and fall of their chests as they breathed—triggered a dense, clear tinkle-clatter-chime of gold, silver, and gemstones.
A young maid in hemp clothing accidentally bumped into one of these "tinkling" women. The maid immediately dropped to her knees, her forehead hitting the floor with a dull thud. The woman didn't even stop, her jewelry chiming as she coldly sentenced the maid to "twenty lashes."
"There's a clear, harsh hierarchy between the family and the servants," Tatsuya noted with distaste.
As he observed further, a massive question arose: "An entire clan of fifty people, and they're all women? I haven't seen a single male family member, not even a boy. That's beyond abnormal."
He thought of the guards he'd seen. "The guards are both male and female, but they are clearly the servant class. Is the Iguro bloodline exclusively female?"
He listened closer. "No sounds of looms, no smell of dye, no movement of trade goods... there is no sign of production or commerce here. How do they afford all that silk and gold?"