An hour had passed since the mana transfer reached its peak, and the air in the bedroom was still heavy with lingering heat. I tried to shift my weight to get out of bed, but I immediately felt a pair of slender, surprisingly strong arms tighten like a vice around my waist. Okita was fast asleep—or at least pretending to be—her face buried comfortably against my back.
I had to spend a good five minutes gently prying her fingers off me, one by one, before I could finally slide out from under the covers.
After quickly getting dressed, I left the softly snoring Shinsengumi captain behind and walked back out into the living room.
I arrived just as the front door clicked open. Kariya walked in, looking exhausted but notably more stable than before, with Sakura staying close to his side. MHXA trailed in right behind them, happily finishing off the very last dango stick from her basket.
I awkwardly rubbed the back of my neck. "Hey. I, uh... apologize for my Servant kicking you out like that."
Kariya shook his head, offering a tired but genuine smile. "It's no problem at all. Frankly, I am already in your debt. You did what I thought was impossible by helping me kill Zouken and actually saving Sakura."
He reached down and gently nudged the small girl. "Sakura, look. This is the kind man I told you about. He's the one who rescued you."
Sakura didn't speak, but she shyly peeked out from behind Kariya's legs, her purple eyes wide and curious as she looked up at me. I felt a pang of genuine warmth seeing her like this. With her skin healthy and the horrific Matou magic purged from her system, she looked like a real, innocent child again. Staring at her, I couldn't help but think she was infinitely cuter in person than she had ever appeared in the Fate/Zero show.
"So, Kariya," I asked, crossing my arms as I shifted the topic to the massive magical war going on outside. "What are you going to do now?"
Kariya's gaze hardened, his one good eye flickering with a cold, focused spite. "Once I'm sure Sakura is fully recovered and safe, I might step down from the War. But... not before I show Tokiomi a thing or two. I want him to see exactly what his 'prestigious' decisions led to."
"I agree," I nodded, officially cementing our alliance. "But you need to be careful. Tokiomi is a threat, but if we're going to survive this and get back at him, we need to watch out for two specific men: Kiritsugu Emiya and Kotomine Kirei. They are far more dangerous than standard magi."
Kariya nodded solemnly, absorbing the names and taking the warning completely to heart.
I looked back down at the little girl, offering her a warm, reassuring smile. "Hey Sakura. Want to see how I healed you? It's a pretty cool magic trick."
She blinked, a tiny spark of wonder momentarily overcoming her shyness. I turned and gestured toward the living room, leading the way.
"Come on, Kariya," I said, pointing to the spot where we were sitting earlier. "Let's get you back to the couch so I can finally fix your circuits."
Kariya carefully lowered himself onto the couch, wincing as the crest worms beneath his skin writhed in agitation. Sakura climbed up right beside him, her purple eyes watching me intently to see this "magic trick."
I took a deep breath, focusing my mind entirely on the principles of Amestrian Alchemy.
I clapped my hands together. A sharp, resonant smack echoed in the living room, instantly followed by the brilliant crackle of pale blue lightning.
Sakura gasped in awe as the alchemical energy danced across my palms. I pressed my hands firmly against Kariya's chest. "Brace yourself," I warned. "Equivalent Exchange isn't always gentle."
I sent the blue alchemical lightning surging directly into his failing magical circuits. Using my deep understanding of human anatomy, I isolated every single parasitic crest worm burrowed inside his flesh.
I completely broke down their dense biological mass, violently transmuting their rotting husks into healthy tissue, muscle, and fresh blood to replace everything they had destroyed. The horrific, pulsing veins on the left side of Kariya's face rapidly smoothed out, the decaying gray tint of his skin flushing with healthy color. I meticulously reconstructed his mangled magic circuits, stabilizing them into a functional, natural state.
When the blue light finally faded, Kariya slumped back against the cushions, taking his first full, painless breath in over a year. He reached up with trembling fingers, touching the smooth, healed skin of his face in absolute disbelief.
"It's... they're gone," he whispered, tears welling in both eyes eye. "All of them."
"You're completely in the clear," I confirmed, wiping a bead of sweat from my forehead. "But for now, we need to keep a close eye on Sakura. We can't let her out of our sight in case she's targeted."
Kariya tensed, his protective instincts immediately flaring as he pulled the girl a little closer. "Targeted? By who? Zouken is dead."
"Actually, the two men I mentioned earlier might come after her," I explained grimly. "Kiritsugu Emiya and Kotomine Kirei. They both play incredibly dirty. If they find out Tokiomi's daughter survived the Matou basement, they might try to use her as leverage against him, or against you."
Kariya's jaw clenched, and he gave a slow, serious nod, fully understanding the ruthless nature of the Grail War.
I looked between Kariya and the little girl leaning against his side. "So, do you plan on officially adopting Sakura then? With Zouken gone, you're technically the new head of the Matou family."
Kariya sighed, a complicated, bitter shadow crossing his face. "My brother, Byakuya, would actually be the one to inherit the headship. I abandoned the family and their magecraft a long time ago."
"That's not how magus families work," I corrected him flatly. "You were always destined to be the heir because your magical talent completely eclipses his. Byakuya is a dead-end. And just so you know... Byakuya was fully aware of what was happening to Sakura in that basement. He was in on it."
Kariya's good eye widened in shock before narrowing into a glare of absolute, murderous fury. He gave a sharp, definitive nod, silently confirming exactly what he was going to do about his brother.
"Besides, the magecraft Zouken was using in that basement was a corrupted, bastardized version of his true power," I continued, crossing my arms. "Before he became that monster, his real name was Makiri Zolgen. His original magecraft was incredibly powerful and strong."
Kariya blinked, the anger in his eye shifting to sudden realization. "Makiri..." he muttered. "I remember... when I was younger, I saw an old, heavy grimoire hidden away in the family study with that exact name written on the spine."
"Grab all of those books when you go back," I instructed firmly. "Makiri was a top-tier mage, literally one of the founders of the Holy Grail system itself. His true magic is highly potent. The only reason a monster of his caliber died today is because his pride and ego made him completely underestimate us."
Kariya looked at me, his expression hardening into pure determination. "I accept. I need that original power if I'm going to protect her properly."
He stood up, his posture entirely different now that he wasn't dying from the inside out. He looked over at the lethargic Sith Lord currently eyeing my transmuted sweets.
"Berserker and I are going to head back to the Matou household right now," Kariya decided. "I'll deal with my brother, secure the estate, and gather all the Makiri training materials I can find. I'll stay there to keep up appearances, but I'd prefer Sakura stayed here with you. It's much more humble... and infinitely safer."
I nodded in agreement. "She can stay as long as she needs to."
Kariya stepped toward the door, but before he turned the knob, he paused. He looked back at me, his expression deadpan but carrying a very serious, protective weight.
"Just... don't do any of your earlier 'fun' while she's around," Kariya warned, his tone completely flat. "If you really need to go at it with your Servant, tell me first so I can at least take Sakura out of the apartment."
My face instantly ignited. I frantically waved my hands in front of me, my composure completely shattering. "Wait, no! That wasn't my idea! I was literally forced by my Servant! It absolutely won't happen again!"
I took a deep breath, forcefully willing the burning heat out of my cheeks to regain a shred of my professional dignity.
"Anyway," I cleared my throat, quickly grabbing a notepad and a pen off the small coffee table. I rapidly scribbled down a very specific, meticulous set of instructions for Byakuya's execution. I tore the sheet off and handed it to Kariya. "When you deal with your brother, make sure you do it exactly like this."
Kariya took the paper, his brow furrowing as his good eye scanned the bizarrely specific steps. "Why? What is the purpose of this?"
"It's the necessary setup for a ritual," I said, keeping my expression entirely serious. "A very, very powerful ritual. Trust me, it will be incredibly beneficial for us."
Kariya didn't question it further. He gave a firm nod, folding the paper and gripping it tightly in his hand. "Understood. Thank you again, Doctor. For everything."
With a final nod, Kariya turned and stepped out of the apartment, closing the door quietly behind him to leave Sakura resting peacefully on the couch.
———
[Kariya Matou's pov]
I walked through the quiet streets of Fuyuki, the cool night air feeling absolutely incredible against my newly healed skin. For the first time in a year, I wasn't in agonizing pain. My body belonged to me again, all thanks to that strange, miraculous Doctor.
I paused beneath the flickering glow of a streetlamp, unfolding the piece of paper he had given me. I re-read the strange, meticulous instructions for Byakuya's demise.
"Thanos...?" I muttered aloud, staring at a specific word written in the margins.
Was it a code? A conceptual catalyst for the magic he intended to use? My brow furrowed in thought. Perhaps the Doctor, despite his incredible alchemical and medical genius, was simply bad at spelling. He most likely meant *Thanatos*, the Greek personification of death. Yes, that made perfect sense for an execution ritual designed to harvest magical energy.
I folded the paper and tucked it safely into my pocket, continuing my walk toward the Matou estate.
Suddenly, the ambient air grew heavy. A sharp, unmistakable pulse of magical energy washed over the city streets, carrying the scent of sea salt. It was emanating directly from the warehouse district near the Fuyuki docks. It wasn't a subtle gathering of mana; it was a blaring beacon. An open challenge from an enemy Servant practically begging for a fight.
Berserker, who had been trailing lazily a few paces behind me, suddenly stopped. Her lethargic posture straightened just a fraction, and she turned her head toward the direction of the docks. Her hand drifted toward the metallic hilt on her belt, and she took a slow, deliberate step away from our route.
"Berserker, halt," I commanded, keeping my voice steady. "We need to secure the Matou estate, retrieve the Makiri grimoires, and deal with Byakuya first. We will go to the docks afterwards."
She almost didn't listen. She let out a soft, annoyed groan, her gaze still fixed on the distant magical signature as she took another defiant step toward the combat zone.
I quickly realized that standard Master commands meant absolutely nothing to her unless I used a Command Seal. But I had seen how the Doctor handled her. I needed to speak her language.
"Listen," I sighed, offering my most convincing tone. "If you behave and follow my orders perfectly, the Doctor will likely give you even more of those premium sweets when we get back."
Berserker completely froze.
She blinked behind her round glasses, her head snapping back to look at me. The annoyance instantly vanished from her expression. In the blink of an eye, she closed the distance between us, standing completely upright right by my side. The lethargic, slow dragging was entirely gone.
Instead, she locked into a perfectly synchronized, highly motivated march right beside me, ready to execute her mission with absolute, terrifying efficiency.
———
The Matou estate was hauntingly silent when we arrived. The heavy, oppressive magical wards that usually suffocated the compound were completely gone, shattered along with Zouken's life.
We moved quickly through the dark, empty halls, making our way straight down to the underground workshop. The smell of burnt ash and ozone still hung heavily in the air from Berserker's earlier rampage.
As we reached the bottom of the stone stairs, I saw him.
My older brother, Byakuya. He was standing near the edge of the pit with his back turned to us. His shoulders were trembling as he stared down at the massive pile of vaporized, lifeless ash that used to be the Matou family's greatest weapon. He was completely paralyzed by the sheer impossibility of the scene before him.
"F-Father...?" Byakuya stammered weakly, his voice echoing in the dead basement. "What... what happened here...?"
I felt a surge of cold, absolute disgust burn in my chest. He knew. He had known every single day what was happening to Sakura in this very room, and he had done nothing but cower and let it happen.
I looked at the lethargic Servant standing faithfully by my side.
"Berserker," I whispered coldly. "Knock him out."
Determined to secure her promised mountain of treats from the Doctor, Berserker didn't hesitate for a microsecond. She moved with a burst of speed that defied her lazy posture, appearing directly behind Byakuya in a blur of motion. Before my brother could even begin to turn his head, she casually brought the heavy metallic hilt of her unlit sword down onto the back of his skull with a sharp thwack.
Byakuya folded like a puppet with its strings cut, collapsing face-first onto the damp stone floor.
"Excellent work," I praised her softly. Berserker gave a tiny, satisfied nod and stepped back, crossing her arms to wait.
I walked over to my unconscious brother, grabbed him by the collar of his expensive coat, and dragged him over to a wooden chair sitting in the corner of the workshop. I hauled him into it, making sure he was propped up securely.
With the target secured, I pulled the Doctor's folded piece of paper from my pocket. I dragged a second chair over, sitting down directly across from Byakuya so I would be perfectly positioned when he woke up.
I smoothed the paper out on my knee, staring at the bizarre, meticulous instructions for the "ritual" the Doctor claimed was so incredibly powerful.
I took a deep breath, steeling my resolve. If this incantation to "Thanatos" was what it took to harness the magical energy necessary to protect Sakura, I would perform it flawlessly.
I cleared my throat, lowered my voice to a dark, imposing register, and began to practice the Doctor's exact dialogue so I wouldn't mess up the spell's cadence when my brother awoke.
"I know what it's like to lose," I read aloud, testing the dramatic weight of the words. "To feel so desperately that you're right, yet to fail nonetheless. It's frightening. Turns the legs to jelly."
I paused, nodding to myself. It was a strange incantation, but it carried an undeniable psychological weight.
"Dread it. Run from it," I continued, narrowing my one good eye at Byakuya's limp form. "Destiny arrives all the same. And now, it's here. Or should I say... I am."
I flipped the paper over to read the final, most crucial line of the ritual—the activation phrase that would theoretically trigger the conceptual harvest of his life force.
"Fun isn't something one considers when balancing the Matou household," I recited, keeping my face completely deadpan as I practiced the required gesture written in the margins.
"But this does put a smile on my face. And now... to make things perfectly balanced, as all things should be..."
I looked at Byakuya's neck, reading the final instruction.
"...I am going to have to snap your neck."