Shinji Matou At Your Service

Plans always change.

Shinji estimated that he would be home before eight o'clock, but when he arrived, it was already close to eight-thirty, which displeased Kariya.

Nightfall is the best cover for mysteries. When night falls, it means that the Servants and Masters will transition from hiding to being active. Although Kariya knew that Shinji's strength and experience made it unlikely for anything to go wrong, he couldn't help but worry. It was an instinct for a parent, something that couldn't be changed.

As the siblings entered the house, Kariya initially wanted to reprimand them. However, when he saw Sakura's joyful expression, he couldn't bring himself to say anything.

The words were on the tip of his tongue, but in the end, he said, "It's getting late, so go take a bath and go to bed early."

"Ah, it's already this late."

Sakura glanced at the wall clock in the entrance and sheepishly stuck out her tongue. She hastily bid Shinji and Kariya goodnight and hurriedly returned to her room.

"She seems a bit livelier than usual," Kariya listened to the sound of slippers hitting the floor and looked at Shinji with a puzzled expression.

Shinji shrugged. "She played with a group of kids in the park, about the same age as her. They got a bit wild and forgot about the ladylike manners Auntie Aoi taught her. Well, it's not a big deal."

"Indeed, it's not a big deal," Kariya agreed wholeheartedly. "As long as Sakura is happy, that's enough."

"Sounds like a silly dad," Shinji muttered under his breath.

"I heard that," Kariya glared at his nephew, not amused. "Now, tell me, why did you come back so late?"

Though Kariya was not married, he knew that no responsible parent would leave their child unattended after sunset.

"It's not Sakura's fault. We found something on the way, and it took some time," Shinji said, pointing downwards, indicating that they should talk in the underground workshop.

...

A few minutes later, the sealed rune-protected underground workshop was opened.

Kariya's face darkened, and his brows furrowed.

"So you're saying you found the monsters summoned by Caster in the nearby underground waterway?"

Shinji's expression was no better than Kariya's. "Yes, I wouldn't mistake those aquatic monsters that resemble jellyfish. I asked Sakura to use her basic magical detection to scan roughly, and there are at least fifty of these monsters in the residential area's underground."

"Fifty! This is troublesome."

Upon hearing this number, Kariya's complexion worsened.

"Indeed. These monsters don't have impressive combat abilities, and a single monster doesn't pose a significant threat to a magi. The problem lies with ordinary people. They can't deal with summoned monsters, let alone this quantity—hmm?"

Shinji's expression suddenly changed. The blood visibly drained from his face, and veins bulged on his forehead, making him look terrifying.

"What did you say?"

Kariya was startled by the inexplicable roar, and he quickly asked, "What's going on?"

Shinji took several deep breaths, trying to keep himself calm. "The latest information from Sensei. To the west of Miyama City, traces of magical energy have been detected in half of the underground waterways, and the total number of monsters exceeds four digits."

Kariya's initial reaction was disbelief. "Summoning magecraft requires a considerable amount of magical energy. Even Lord El-Melloi II or Tohsaka Tokiomi wouldn't have enough magical energy to waste on summoning so many Servants, let alone an irregular Master. We haven't received any reports of people being killed by the police today. How did Caster manage to do this?"

"That's not Caster's magical energy, but the ability of Caster's Noble Phantasm. In the two encounters, Sensei deduced that Caster isn't summoning the monsters using his magical energy but relying on Noble Phantasm. His grimoire, 'Prelati's Spellbook,' is a magical energy reactor that can activate the highest-level magecraft, the Grand Ritual of the Highest Rank, regardless of the magi's magical energy."

Caster's sole Noble Phantasm is called "Prelati's Spellbook." It contains forbidden knowledge about ancient evil gods that existed before the birth of humanity. Its continuous automatic large-scale summoning has been evaluated as an "A+ rank Noble Phantasm." Given enough time, Caster can summon thousands of monsters, let alone a thousand.

"And because they are aquatic monsters, summoned in the water and hidden underground, it is difficult to detect them due to multiple barriers. Even Sensei and the other Servants active on the surface haven't noticed the changes beneath their feet."

"This situation is getting desperate," Shinji sighed heavily, his heart burdened. He wouldn't regret his actions against Caster's group because it had indeed saved some lives that might have been lost. However, Caster's behavior was ultimately caused by him, and he needed to take responsibility for it.

"We can't waste any more time. We can't let Caster continue summoning. I will immediately go and clean up the underground waterways."

Saying this, Shinji took out a fresh map from a nearby bookshelf. It was a detailed map of Fuyuki City's underground waterways, which had been obtained through connections with the police. Originally just an accessory to the police map, it unexpectedly came in handy now.

"I'll go too. With Berserker here, we can clean up faster."

Kariya drew a large circle on the map, covering one-third of Fuyuki City with the Matou family as the center. "I'll take care of this area. If the monsters are as weak as you say, my magical energy will be enough to last until dawn."

Shinji hesitated for a moment but eventually nodded. "I'll leave that area to you, Uncle. It's frustrating to be led around by Caster, knowing that it's just a distraction."

"Let them have their moment of triumph for now. Once Sensei finds them, we'll take back everything, with interest," Kariya patted his nephew's shoulder and reassured him. "By the way, should we inform the Church? They are the ones who changed the rules; they should be the ones dealing with this."

"Let's just inform them symbolically. I don't think they'll be of much help."

Only two people from the Holy Church were stationed in Fuyuki City: Kotomine Kirei and Kotomine Risei.

Kotomine Kirei was a warrior, not a magus, and had poor compatibility with the magical creatures summoned using magecraft. Purely mysterious creatures needed to be dealt with using mysteries, and physical methods were less effective.

Kotomine Risei, on the other hand, was more suitable for this kind of work. However, he didn't care about the lives of ordinary people, and his attention was currently focused on Tokiomi. It was more reliable to hope that Tokiomi would give up his aristocratic elegance and dignity and go into the underground waterways.

After dividing their respective areas of responsibility and making copies of the underground waterway maps, the uncle and nephew set out separately.

Kariya had Berserker, with the highest parameters, by his side. With Berserker's incredible A-rank strength, he didn't need to use Noble Phantasms or other skills. He could simply tear apart the monsters with brute force.

Kariya's approach was as straightforward and brutal as his Servant's fighting style. Using pre-set detection runes, he followed the fluctuations of magical energy to find his targets. Berserker would materialize, tear apart the monsters with his hands, and then dematerialize. The entire process took less than three seconds, minimizing magical energy consumption. That's why Kariya said he could last until dawn.

Shinji couldn't be as effortless as Kiriya. Even with magical reinforcement, his strength was barely at the E rank, roughly on par with the cannon fodder monsters. However, he had Perseus' "Harpe," a scythe blade that surpassed the rank of "Caliburn" and other Noble Phantasms. It was far beyond what the monsters could withstand.

The effect of "Harpe," which prevented wounds from healing, also effectively countered the monsters' regenerative abilities. It was because of this trump card that Shinji didn't recall Scathach and chose to act alone.