Matou Kariya emerged from the damp, fetid nest of insects, his hand trailing behind as he spilled out the bugs that had burrowed into his ears.
With nothing but his hands for support, he dragged himself up onto the platform and silently donned the clothes laid out for him.
At the top of the staircase, he opened the door to the lavishly decorated sitting room, and just as he expected, the shadow was waiting.
Or rather, the old man inside the shadow.
The large meeting room, designed to the owner's tastes, contained no furniture save for the bare essentials. The barren openness of it all made the space feel desolate.
No lights were lit. Aside from the moonlight slipping through the curtains, there was no illumination. To most, it would be nearly impossible to see anything in this gloom.
But Matou Kariya was no longer most. His eyes had long since been replaced by visual familiars.
"How are you feeling today?"
A rasping voice emerged from the old man's mouth, something not quite human.
"As usual. The worms in my body have been replaced. The engraved ones are functioning perfectly."
A year ago, Kariya returned to the Matou estate and began preparations for the Holy Grail War. Given the old parasite's cruelty, he'd assumed the training would be agony, more torment than transformation. Yet surprisingly, aside from the expected pain, it hadn't been as horrific as he'd feared.
In fact, he was far stronger than before, in both magic and combat.
At first, the thought of becoming little more than a shell filled with insects, with only his brain and heart preserved, had made him sick with fear. But now, looking at the results, he had to admit, it worked.
The Marking Worms compensated for his inferior magical circuits. His body, now a nest for parasites, granted him resilience and the ability to swap familiars on the fly. Sustaining a high-cost Servant and fighting in tandem? No longer a pipe dream.
Zouken claimed it was all part of his secret to longevity. If he didn't have a goal to pursue, he would never have wasted such resources on anyone else.
Even so, the cost remained: Kariya had only a month left to live.
But during this month, he would be a monster the other magi would never forget.
Under those terms, he could accept the nest. He could even call it a workshop.
"Could this be the true inheritance of the Matou line?"
He recalled the horrific scenes of flesh and blood devoured by insects that he had witnessed as a child, and the question left him unsettled.
"Of course not," came the cold reply. "You think the Law of Water, the true core of our craft, could be grasped by someone like you? Feeding flesh to insects is just a diluted, degenerate version of the art, created only because you lack the qualifications."
Zouken's sneer cut through the air. "If not for you worthless descendants, I wouldn't have had to adopt the Tōsaka girl."
He scoffed again. "Even that heir, who I had little interest in, turned out defective. If I don't find a solution soon, this bloodline will rot and end with you all."
Kariya ignored the rant. His emotions were dulled, an expected side effect of having most of his body hollowed out, but his obsession remained.
"Where's Sakura? My transformation is complete. You didn't go back on your word, did you?"
"Of course not. How could I possibly lie to my dear child?"
Zouken's sickening gaze lingered on Kariya, eyes gleaming with twisted appreciation, as though admiring a masterpiece of his own design.
He clapped lightly.
A young girl in a violet dress stepped in.
She was unnaturally adorable, like a doll sculpted by a master's hand. But her eyes, those lifeless, empty eyes, made it clear something inside her was gone.
"Sakura…"
Kariya approached quickly. His palm split open, and a tiny insect emerged, fluttering gently toward the girl.
"Uncle Kariya…"
Her voice was soft. When she saw the insect, her eyes flickered with fear, but she didn't move away.
"…I'm sorry, Sakura. I didn't mean to scare you."
Kariya extended his hand toward her, but stopped short.
Remembering what he had become, he let his arm fall and recalled the insect. It crawled back beneath his skin, and he processed the sensory data it had gathered.
From the side, Zouken watched with a grin. The way Kariya writhed, the grotesque movement beneath his skin, it was all so deliciously pathetic.
"Well, Kariya?"
Zouken's voice was oily. "Do you still think it was a mistake to come back a year ago?"
"You saved the Tōsaka girl before she could be dropped into the worm pit. And look, she's unchanged. Not a single time has she entered the hive. Isn't that proof of my sincerity?"
"Then explain her condition!" Kariya snapped.
"Tch. Have you already forgotten our agreement?"
Though Zouken's words were casual, there was no warmth, only perversion and malice in his tone.
"I said I wouldn't touch the Tōsaka girl. But she bears the Matou name now, and as the heir, it's only natural that she be educated about her family's practices and circumstances."
"It seems that... the more unpleasant details had a stronger effect on her than I expected. She shut down. Went silent."
"You bastard!"
"No, you're the bastard," Zouken spat, his voice dripping with revulsion. "If you were of any use, we wouldn't be in this state. Even if I had thrown the girl in the pit, you'd still have agreed to fight. So quit pretending to be noble."
Then, as if to emphasize his disgust, Zouken uttered a sound, half wheeze, half snarl.
Kariya's body immediately contorted. Something inside him twisted and convulsed. He dropped to his knees, gasping in pain.
"I know…" he rasped. "I'll kill that man, Darnik. I'll kill him quickly."
His voice was steel now, his eyes burning with resolve.
"You'd better," Zouken muttered. "Because the moment you fail, this child goes into the pit. She'll undergo the transformation I delayed a year ago."
"And until then, you will not lay a hand on her. After I kill him, Sakura is free to leave the Matou household. That's what we agreed."
"I promise."
"…Then get moving. Berserker's relic is already prepped."
Forcing himself to abandon hesitation, Kariya hardened his heart and turned away from Sakura. He descended toward the basement.
"…He's grown up," Zouken said softly, a smirk tugging at the corners of his mouth.
Then he turned to Sakura, his voice gentle, falsely so.
"Sakura, you've learned self-hypnosis by now, haven't you? You can activate your magic circuits?"
"Yes, Grandpa," she answered without emotion.
"Good. The output's low, but the imaginary number affinity is enough to sustain Caster."
A cruel idea bloomed in Zouken's mind. The image of Kariya's face when he discovered the truth would be a sweet reward.
He was a man of his word. He would let Sakura leave the Matou family.
But he'd never said where she'd go.
Certainly not back to Tōsaka.
Kariya's naive sense of goodness disgusted him.
"Come with Grandpa in a few days," he said in a voice soaked in false kindness. "You'll meet someone new. From now on, he'll take care of everything for you."
Zouken looked at her delicate, pale hands and sneered.
"I'm sure the creatures will like you very much. So much, in fact, that you may regret not throwing yourself into the worm pit instead."