The morning light of Asakusa carried the scent of charcoal and street food, washing away the fatigue of Ryousuke's all-night sprint.
"Boss, one bowl of noodles!"
Ryousuke sat at a stall, still feeling a lingering chill. Only he knew the terror of being chased by a boisterous, over-affectionate Shinjuro Rengoku. Damn it! A man's backside should be for sitting and business, not for Hashira-level hugging!
After a quick meal, he began wandering the streets. Compared to the rural villages, Asakusa was a different world. Street vendors lined the roads, their shouts mixing with the ringing bells of rickshaws and the sweet aroma of rice cakes and tempura.
He spent hours visiting pharmacies and clinics. The responses were always the same: a blank stare or a suspicious glare. There was no sign of the mysterious Doctor Tamayo.
"Tch. Looking for a needle in a haystack," Ryousuke muttered.
Tamayo had hidden from Muzan for hundreds of years. Between Yushiro's cloaking Blood Demon Art and her own cautious nature, she was a ghost.
Ryousuke sighed. Then, a simple, blunt idea struck him. If he couldn't find her, he'd make her find him.
For the next half-day, a strange rumor began to drift through the busy alleys of Asakusa. A young traveler was looking for a doctor, sighing to anyone who would listen, whispering his woes to friendly stall-keepers.
"Alas, my older brother has been afflicted by a strange curse. When he is wounded, the cuts heal instantly. He can walk in the daylight and looks human, but..." He would trail off, looking pained.
"But what?" the curious locals would ask.
"But he cannot survive without human blood! If he doesn't drink it every few days, he loses his mind in agony. I've seen every famous doctor, and they all say it's a 'Soul-Leaving Sickness' from ancient scrolls. If anyone can cure him, we'd give our entire family fortune!"
The bait was laid. To someone like Tamayo, who harbored a centuries-old grudge against Muzan and a doctor's obsession with the demonic biology, the rumor of a demon who conquered the sun but still needed blood was irresistible.
Ryousuke also had a fleeting thought: What if I find the Blue Spider Lily at Tanjiro's house and have Tamayo turn me into a demon? I'd become the 'Ultimate Lifeform' like Kars! Infinite life, infinite System points... I'd be invincible!
[Wake up, you dog of a Host. Stop dreaming.~] The System splashed metaphorical cold water on him.
"What? Is there a setting preventing me from becoming a demon?"
[Not exactly, but use your 'dog-brain' for a second.~]
Ryousuke bristled but realized the catch. Tamayo had been free for over 200 years. In that time, she had treated countless terminal patients, yet only Yushiro and Chachamaru (the cat) successfully became demons.
Muzan could turn people with a flick of his wrist, but Tamayo had altered her own body. The concentration of Muzan's blood in her was thin. Converting a human took a massive amount of time and had a high failure rate.
Moreover, the stronger the human—especially one using Breathing Styles—the harder the transformation.
[See? Not totally stupid.~] The System yawned. [If it were that easy, Tamayo and Kagaya would have just turned all the Hashira into demons to jump Muzan during the final battle. It's a plot-armor patch by the author.]
Ryousuke rolled his eyes. Fine, no shortcuts. Back to the grind.
At dusk, as the shadows lengthened, Ryousuke sat at another noodle stall. A pale boy with lavender-tinged hair and a permanent scowl appeared beside his table.
"I heard you are looking for a doctor who can treat a 'strange sickness'?" Yushiro's voice was flat and cold.
Don't laugh. Keep it together, Ryousuke told himself. He looked up with practiced desperation. "You have a lead?"
"Follow me."
Yushiro turned and walked. Ryousuke followed him through a maze of winding alleys where the light and scenery seemed to ripple unnaturally—Yushiro's cloaking seals.
A stone wall suddenly parted like water. Behind it lay a hidden mansion, shielded by tall trees that blocked out the sun even at noon. The door was open.
A woman stood there, wearing an elegant kimono, her dark hair pinned back. Her face was gentle, her aura like ancient jade.
A MILF! A top-tier married-woman aesthetic! Ryousuke thought, his 21st-century brain briefly short-circuiting.
Before Yushiro could introduce him, Ryousuke spoke with a chilling calm. "Lady Tamayo. A pleasure to finally meet you."
The words hit the quiet courtyard like a boulder dropped into a pond.
"You?!" Tamayo's eyes shrank, her body recoiling instinctively. A Slayer? Or a demon sent by Muzan?
Yushiro reacted instantly. "YOU BASTARD!!!"
Ryousuke didn't hesitate. Before the boy-demon could move, Ryousuke blurred. He seized Yushiro's wrists, pinned them behind his back, and slammed him face-first into the dirt, his boot pressing firmly into the boy's spine.
BAM!
"Ugh!" Yushiro groaned, his back feeling like it was about to snap. He struggled, but Ryousuke's foot was like a mountain.
Ryousuke didn't even look down at the pinning victim. His eyes remained fixed on Tamayo. A slow grin spread across his face.
"Lady Tamayo, I know your story. I suggest you don't move."
He pulled out his white Nichirin blade and drove it into the ground beside him. "If you try to use a Blood Demon Art, I'll kill him."
"Stop! Let go of Yushiro!" Tamayo cried out, her hand which had been reaching into her sleeve for a chemical agent slowly dropping.
"Don't worry about me, Lady Tamayo! Run! Get out of here!" Yushiro roared, veins popping on his forehead. He was the ultimate "Simp"—willing to die if it meant Tamayo stayed safe.
Tamayo sighed. Run? To where? This Slayer knew her name and her location. He was prepared. And his strength was far beyond what she or Yushiro could handle.
A few heavy seconds passed. Tamayo drew her hands from her sleeves, surrendering to the situation. "You win. Who are you, and what do you want?"
Seeing Tamayo's forced submission, Ryousuke felt a strange twinge. So this is what it feels like to be the 'NTR villain' in a story... kind of a weird vibe.
He shook the thought away and smiled. "Relax, Lady Tamayo. I didn't come here to hunt you."
Tamayo looked at him skeptically. You broke into my house, pinned my companion, and drew your sword. And now you want to talk?
"I want to discuss a partnership," Ryousuke continued.
"Partnership?"
"Yes. I want to kill Muzan Kibutsuji."
The name acted like a curse, freezing the air. Tamayo's expression went through a whirlwind of emotions. Every Slayer wanted Muzan dead, but Tamayo's hatred was personal—she had eaten her own husband and children because of him.
"I know brute force isn't enough," Ryousuke explained, lifting his foot off Yushiro but staying alert. "I need your expertise. I need you to research a medicine that can turn demons back into humans. That is the only weapon that can truly cut off Muzan's roots and deliver the killing blow."