After taking Sakura Matou away from the Matou household, Zuke completed Rin Tohsaka's task.
Of course, helping Rin was merely incidental; Zuke's primary goal was to see if he could advance the main quest.
How should he proceed with the main quest? Since the goal is to obtain the Holy Grail, the best way forward is to eliminate the other participants in the Holy Grail War.
As for Tohsaka Tokiomi and his Servant, Zuke planned to save them for last, since he was currently Rin's Servant and should give her a bit of face.
Accepting Rin's request to visit the Matou household was also an excuse to see if Matou Kariya was there.
Although the old worm Matou Zouken hadn't planned to participate deeply in the Fourth Holy Grail War, he still sent in a participant on the principle of "it doesn't hurt to try."
Or rather, the participant had volunteered for the Holy Grail War—Matou Kariya, the nominal grandson of Matou Zouken.
Simply put, Kariya was a lovesick fool, intent on "saving" Aoi Tohsaka and her two daughters from the Tohsaka family.
To protect Sakura from Matou Zouken's torment, he volunteered to participate in the Holy Grail War, hoping to use the Grail to secure Sakura's freedom.
However, as Kariya didn't have outstanding magical abilities, Matou Zouken reformed his body with insect-based magic, replacing his magical circuits with command worms, giving him the power to participate in the war.
If everything went as expected, Kariya would likely have already been selected as a Master by the Grail.
Zuke's visit to the Matou household was to see if he could capture Kariya. If Kariya had already summoned a Servant, Zuke planned to eliminate it, which would likely advance the main quest considerably.
If Kariya hadn't summoned one yet, Zuke would force him to summon it on the spot and then defeat it right away for the same result.
Unfortunately, Kariya was nowhere to be found this time, and Zuke wasn't sure where he'd gone. So, he settled for gaining a meager 5% synchronization rate from Matou Zouken.
Since he couldn't find Kariya, he had no choice but to target the other participants.
...
"I'm back, mission accomplished."
Back at the place where Rin was staying, Zuke quickly found his young Master.
However, he was surprised to see Rin seemed less than enthusiastic about his return and instead appeared a bit upset.
"Hmm? What's wrong? You look like a kid who's just been sold by her parents."
"Who's been sold by their parents!?"
With his remark, Rin instantly bristled, her upset expression replaced by a scowl as she glared at Zuke.
At least she seemed more animated now.
"I told my mother about you, and I said you could help Father win the Holy Grail War…"
Angered by Zuke's remark, Rin regained some energy but still looked unhappy as she spoke with her head lowered.
"But my mother refused. She told me not to tell Father about this and asked you to stay home and not go out."
Zuke understood: Aoi Tohsaka didn't want Rin to get involved in the Holy Grail War.
Aoi Tohsaka, Rin's mother, came from a family of magicians, the Zenjou family, though unlike the prestigious Tohsakas, her family had declined, leaving only her bloodline with any value.
Unlike Tokiomi, who was willing to pay any price to fulfill his ambitions, Aoi had a gentler and less rigid approach to life.
She was supportive of Tokiomi's endeavors, but without his guidance, she had her own thoughts. Her hope was simply that her daughter could live peacefully.
To Aoi, the Holy Grail War was brutal, and she'd moved herself and Rin to a place far from the battlefield to avoid getting caught up in it.
Naturally, she didn't want Rin drawn into its murky depths.
"She told me to believe in Father's victory, that I don't need to help."
Rin pouted, clearly feeling her capabilities were being underestimated and looking defiant.
"What do you think, Berserker? Should I really just stay home?"
"The Holy Grail War is indeed brutal."
Zuke didn't sugarcoat things, speaking honestly to Rin.
"Didn't you just ask me to check on your sister? Do you want me to tell you what I saw at the Matou household?"
...
"What?! How could the Matou family do something like that!?"
After hearing about the situation at the Matou household, Rin's face turned pale—she hadn't anticipated such horror.
If it weren't for her concern as an older sister, sending her Servant to check on Sakura, her sister would have likely been subjected to the Matou family's cruelty.
The only relief was that Zuke said he had rescued Sakura and found her a temporary place to stay.
However, when he mentioned that Sakura didn't want to return, Rin's expression darkened a bit.
"If you're unsure, wait until tomorrow and check the news. There's a good chance the Matou household's insect nest will make headlines."
Zuke shrugged. Before leaving, he had called the police, so police and firefighters were probably fighting a gruesome battle with the "bug monsters" by now.
"Of course, some magicians may try to suppress this news to prevent magic from being exposed to the public."
Magic, as a mysterious art, weakened with increased awareness, so magicians took great pains to keep it a secret.
The Matou insects, too, were a form of magic that some might want to cover up.
"The Holy Grail War is like this. Even innocent children like your sister find it difficult to stay out of it."
Zuke smiled at Rin.
"Knowing this, do you still want to take part?"
He looked at her, ready to find another way to participate if she decided to back out.
"...No, I want to join."
Hearing Zuke's words, a fierce resolve ignited in Rin's eyes.
"I am a daughter of the Tohsaka family! How could I retreat? That would make me look useless."
Though young, Rin's strong-willed nature was clear.
"I'll win the Holy Grail War and prove to Father that I'm not a child anymore! My Servant is even stronger than the one he summoned!"
Although she respected her father, now that she had chosen to participate, she wouldn't back down.
"Berserker! You'll win, won't you?!"
"Of course! Who do you think I am?"
Zuke grinned at the now-determined Rin and gently patted her head.
"Leave it to me."
To be continued…