Susamaru's temari ball demolished another section of the clinic wall. Debris scattered everywhere as I dove behind overturned furniture.
"Yushiro!" Tamayo's voice cut through the chaos. "Protect Akira-san!"
"What? But Tamayo-sama—"
"He's our hope against the demons! If Muzan gets hands on that cure and Akira-san, we would lose one of the most important person in this war!" Her tone left no room for argument. "Keep him alive!"
Yushiro's expression twisted between devotion to Tamayo and clear reluctance, but he moved toward me anyway. "Stay behind me, human."
I watched Tanjiro engage Yahaba, water breathing forms flowing as he dodged those arrow techniques. The kid was good, but Yahaba's arrows were relentless, bending mid-flight to track their target.
Susamaru giggled, another ball forming in her hands. "This is fun! Muzan-sama will be so pleased when I bring him the cure along with you!"
She threw. The ball curved mid-flight, aimed at my head.
My body moved before I thought about it. Viltrumite physiology kicked in—I didn't just dodge, I moved fast enough that the ball seemed to slow down. My hand shot out, caught it mid-flight.
The impact should have shattered every bone in my arm. Instead, I felt... nothing. Just the smooth surface of the temari against my palm.
Susamaru's manic expression froze. "What?"
I crushed the ball. It compacted in my grip like paper, then disintegrated.
"Impossible!" Susamaru shrieked. "Those balls can destroy buildings!"
"Akira-san?" Yushiro stared at me, his protective stance suddenly seeming unnecessary.
Before I could respond, Susamaru went wild. Three balls launched simultaneously—one at me, two at Nezuko who was helping Tanjiro.
"Nezuko!" Tanjiro's scream cut through everything.
The balls hit. Nezuko's body was thrown backward, slamming into the wall with brutal force. Blood—demon blood, but still blood—splattered across the floor.
Tanjiro ran toward her but Yahaba's arrows forced him back, engaging him in the battle.
Tamayo was already moving, medical instincts overriding everything else. She reached Nezuko, hands glowing with her Blood Demon Art as she began emergency treatment.
Yushiro positioned himself between them and Susamaru. "Tamayo-sama, I'll—"
"Don't worry about me," I said, stepping forward.
The divine sword materialized in my hand. I hadn't consciously summoned it—the weapon responded to intent, appearing when needed. Its blade gleamed with an otherworldly light that seemed to drink in the surrounding darkness.
The temperature dropped.
Every demon in the room shivered. Tamayo's hands faltered mid-treatment. Yushiro took an involuntary step back. Nezuko, even injured, whimpered. And Susamaru—
Susamaru's manic expression cracked into something resembling fear.
"What... what is that?" Her voice lost its playful edge.
I rolled my shoulders, getting comfortable with the sword's weight. "This? Just a little something I picked up. Don't worry about it."
Thunder Breathing techniques flooded my mind—a gacha reward I'd never actually used in combat. First Form: Thunderclap and Flash. The stance came naturally, muscle memory from knowledge that wasn't mine.
"You know," I said, taking a step forward, "I was having a nice conversation before you crashed in here." Another step. Susamaru backed up.
"Stay back!" Susamaru threw another ball. I didn't dodge—just swung the divine sword. The blade cut through the temari like it was made of smoke.
"And you seem fun," I continued, grin spreading across my face. "All that energy, that enthusiasm. Shame you're trying to kill me. We could've been lovers you know?"
"Shut up!" More balls, a whole barrage. I wove through them, Thunder Breathing making my movements sharp and precise. Each step placed me exactly where I needed to be.
"I mean it though. That laugh of yours?" I closed the distance between us. "Adorable. Unhinged, sure, but adorable. You're like a homicidal pixie."
Susamaru's face flushed. "Are you... Mocking me?!"
I deflected another ball with the flat of my blade. I didn't bother to waste my words on her anymore, she was fixated on getting her ass kicked, so why should I rob of her fun?
"Die!" She launched herself at me, claws extended, abandoning her temari entirely.
Thunder Breathing, First Form. My body moved, not a step but a thunderbolt. The world blurred. I was behind Susamaru before she realized I'd moved.
The divine sword hummed in my hand, its edge pressed against her neck.
"Last chance," I said quietly, the playfulness gone. "Walk away. Tell Muzan you couldn't find me and you will live."
Susamaru went still. For a moment, I thought she might actually consider it.
Then she laughed. That same manic giggle. "Muzan-sama would do worse things to me than you ever could. At least dying to you will be quick!"
She threw her head back, trying to impale herself on my blade.
I obliged.
The divine sword cut clean. Susamaru's head separated from her body, both already disintegrating into ash before they hit the ground. Her final expression wasn't fear—it was relief.
Across the room, Tanjiro's blade found Yahaba's neck. Water Breathing, Tenth Form. The arrow-eyed demon's head rolled, body crumbling to ash.
Silence fell over the destroyed clinic.
I dismissed the divine sword, watching it fade back into whatever space it occupied when not manifested. My hands were steady. No trembling, no shock. Just... quiet acceptance of what I'd done.
*Rank 3 Gacha Ticket acquired,* the system chimed in my head. I mentally filed it away for later.
Footsteps approached. Tamayo, Yushiro, Nezuko—now healed—and Tanjiro formed a semicircle around me. Four pairs of eyes, all carrying the same question.
"Are you part of the Demon Slayer Corps?" Tamayo asked carefully.
"No."
"But that technique, that sword—"
"I'm just a doctor." I shrugged. "One who travels a lot and picks up things along the way. Medical knowledge, combat skills, weird weapons. You know, normal doctor stuff."
Yushiro made a noise that suggested he thought I was full of shit. Fair assessment.
I turned to Tanjiro. "More importantly—have you made your decision? About Nezuko?"
Tanjiro's hand went to the bottle in his pocket. He looked at his sister, at Tamayo still covered in demon blood from healing her, at the destruction around us.
"I want to turn her back into a human."
Nezuko looked up at him, then at me, then back to her brother. She nodded slowly, reaching for her bamboo muzzle.
"If that's what you want," I said. "We can do it right now."
Tanjiro pulled out the HWL bottle with shaking hands. "Nezuko, I'm going to use this. You'll be human again. We can go home, live normally—"
She removed her muzzle, placed her hand over his. "Brother, it's okay."
The bottle tipped. Clear liquid poured into Nezuko's mouth. She swallowed.
For a moment, nothing happened.
Then blue light erupted from her body. Gentle, warm, wrapping around her like a cocoon. Her demonic features—the claws, the fangs, the inhuman gleam in her eyes—all faded. The light grew brighter, then suddenly vanished.
A human girl stood there. Brown hair, pink eyes now without any demonic tint. She looked exactly like she must have before that night Muzan came.
"Nezuko?" Tanjiro whispered.
"Brother." Her voice was clear, human, untainted by demonic distortion.
They collided in a hug. Both were crying, Tanjiro's shoulders shaking with sobs he'd probably been holding back for months. Nezuko clung to him, tears streaming down her face, saying "Brother" over and over like a prayer.
Tamayo's hand covered her mouth. "It actually works. Complete reversal, no trace of demon blood remaining..."
"Incredible," Yushiro breathed. "Centuries of research, and this human accomplishes it with a simple potion..."
I watched their reactions, then asked, "Want one? I've got spares."
Both demons' heads snapped toward me.
"You're willing to give them to us?" Tamayo's voice carried disbelief.
"Only if you don't have issues with turning back human. You won't be as strong. Fighting Muzan would be..." I trailed off meaningfully.
Tamayo was quiet for a long moment. Then: "Aren't you afraid? Muzan will keep on hunting you. Knowing you can cure demons, he won't let—"
"Fear?" I couldn't help the surprised laugh "It's not that big a problem. I'm pretty good at protecting myself. Even against him."
The look all four of them gave me clearly communicated: *You're either insane or suicidal.*
"I'm serious," I protested. Their expressions didn't change. "Fine, don't believe me."
I sighed. "It's probably better if you two stay as demons anyway. Also, it would be better if we join the journey don't you agree?"
"Don't try to bring us into this!" Yushiro interjected but Tamayo already seems to agree to it as she nodded in affirmation.
"What about them?" Tamayo gestured to Tanjiro and Nezuko. "What about their safety? Muzan will target them too now. And with Nezuko turned into a human, Tanjiro has lost a significant advantage"
I walked over to the siblings, placed a hand on each of their heads. They looked up at me, confused.
"I've adopted these two," I announced " From now on, it's my responsibility to take care of these two, until I kill Muzan with my own blade."
Silence.
Then—
"WHAT?!" Tanjiro and Nezuko screamed in unison.
"ADOPTED?!" Yushiro's voice cracked.
I grinned. "What? I can't let them wander around unprotected after this. So now they're mine. I'm responsible for keeping them alive until Muzan's dead. Any objections?"
"You can't just—" Tanjiro started.
"I'm not—" Nezuko tried.
"This is—" Yushiro managed.
Tamayo, for her part, just looked at me with an expression somewhere between exasperation and respect. "You're the strangest doctor I've ever met, Akira-san."
"I'll take that as a compliment."
The siblings were still protesting, but I could see the tiny bit of relief in both their expressions. They weren't alone anymore. Whatever came next, they'd have backup.
And honestly? Looking at these two kids who'd already been through hell and were somehow still good people?
'This is going to be so much fun'