Trifas, Yggdmillennia Castle.
"My king, there's a disturbance at the boundary field. According to the familiars, it appears to be Red Faction's Berserker."
Darnic respectfully stood at Vlad III's side, reporting as they observed images transmitted by familiars, showing Red's Berserker cutting a straight path through the dense forest.
Its goal was crystal clear: charging directly toward Yggdmillennia Castle—their stronghold.
"Did the concealment boundary fail?" asked the Saber of Black's Master from below the hall.
"No, it's functioning perfectly. But Berserker seems to have somehow pinpointed our location by another method."
Darnic himself was puzzled by how Berserker managed to locate their base. The Servant evidently possessed unique tracking abilities.
"Besides Berserker, are any other Servants approaching?"
Vlad III inquired. Matters concerning the bounded fields and familiars weren't handled by him directly; he relied entirely on Darnic's detailed reports.
"None. Possibly due to Red Archer's injuries, her movements remain severely restricted. According to familiars, Red Rider initially attempted to halt Berserker, but failed."
"After Berserker entered deep into our territory, Rider gave up pursuit and abandoned Berserker entirely."
Darnic conveyed the situation calmly.
"In other words, Berserker's coming alone?"
Darnic nodded. Judging purely by presence, this Berserker was significantly inferior to the Knight King who had stormed the Red faction alone. Furthermore, the Black faction certainly wouldn't arrogantly send merely two Servants against the invader, as Red had previously done.
"Then we shall capture Red's Berserker alive. Caster, can you transfer its contract to one of our Masters?"
Caster nodded affirmatively. After all, not everyone was a peculiar case like Shirou Emiya.
"All forces, mobilize and subdue Berserker!"
Meanwhile, where exactly were Shirou Emiya and Arthur?
To understand this, one must return to earlier in the day—
Simply put, Darnic had sought out Shirou in the castle courtyard, interrupting Arthur's training session with him.
"Assassin's Master has sent word that they'll reach Trifas tonight. However, Red Saber has been spotted along their path, so we require you to meet and escort them safely."
At least, that was the reason Darnic gave Shirou openly.
But in truth, Darnic knew very well that the message had not been sent by Assassin's Master at all.
Did Darnic not intimately know the magi of his own clan?
This letter was certainly not penned by Sagara Hyouma, the supposed Master of Black Assassin. Given Sagara's personality, it was impossible he'd write such a detailed letter to inform him so conveniently.
Most likely, Sagara was already dead.
Yet someone had to investigate, so after careful consideration, Darnic decided to send Shirou Emiya, an outsider, to face this Assassin—who likely no longer belonged to the Black faction.
If this new magus still intended to serve the Black faction, Darnic would gladly accept them. There was no hatred between magi, after all.
However, if this magus was hostile, it might be a dangerous trap.
He should've informed his Servant immediately, but strangely, he'd chosen to conceal the information for now. Reading the letter, Darnic felt an oddly familiar sensation, though he couldn't recall exactly whose voice it reminded him of.
He'd used magecraft to reveal the shadow of the letter's author. The reflection showed a slender woman. But the trembling of her hands had clearly shown she'd written the letter under coercion.
Darnic needed to know exactly what intentions this mysterious replacement Master held.
Until he gained more information, he didn't plan to inform Vlad III of this troubling situation.
Thus, Shirou found himself once again on another overtime assignment.
For Shirou, staying at the castle meant enduring oppressive tension anyway, so he gladly accepted Darnic's suggestion, heading directly to the given location.
His reasoning was solid, wasn't it?
Besides, Shirou genuinely wished to see firsthand just what kind of Servant could be labeled a "serial killer."
Thus, as Vlad III was mobilizing the Black Faction to intercept Red's Berserker, Shirou and Arthur were heading toward the outskirts of Trifas.
Perhaps thanks to Darnic's earlier arrangements, the citizens of Trifas hardly ventured outside after nightfall.
Only a few scattered drunkards or late workers still walked the empty streets. By night, the normally bustling town became eerily desolate, the streets completely silent save for their footsteps and the howling wind.
Wisps of white mist slowly rolled in, blanketing the entire town under its eerie veil.
"Cough—!"
Shirou suddenly choked, clutching his throat as he inhaled the thickening fog. Violent coughing racked his lungs, accompanied by a searing pain that surged through his chest.
"Master!" Arthur swiftly caught Shirou as he staggered, his expression instantly grim.
"This fog—it's poisonous!"
Arthur felt its effects himself. Without his [Instinct] skill, he'd likely be unable to discern the direction clearly. The fog's sudden arrival had greatly hampered his agility as well.
But now wasn't the time to dwell on that.
His first priority was removing Shirou from this lethal mist.
This fog was likely the Noble Phantasm of the very Assassin they were supposed to welcome back to Yggdmillennia Castle. Ordinary humans caught within it would surely perish in mere moments. Even a trained magus would last only slightly longer.
Arthur swiftly decided: He needed to get Shirou out immediately.
Yet at that very moment, a sharp, deadly sense of danger flared from behind him.
Without hesitation, Arthur swiftly ducked his head forward.
A flash of silver gleamed through the thick mist, slicing through the air exactly where his head had just been.