Mount Enzou, Underground Cave.
In every world, whenever the Holy Grail War occurred in Fuyuki City, this place would inevitably become the convergence point of chaotic fates.
After all, it was the ideal location for the Holy Grail to manifest.
"This is the place?"
Standing outside the cave, Ritsuka looked at the entrance before her and swallowed hard. "It feels eerie… My skin is crawling. Are Saber and the Greater Grail that the department head mentioned inside here?"
"Since that's what he said, there probably isn't any mistake. He's never wrong when it comes to finding things."
"Yes, regarding my brother, he would never give us incorrect information. Please don't worry, Senpai."
Though their tones differed, both Hinako and Mash showed unwavering trust in Naoki.
(I'm a bit confused about what Akuta-Senpai really thinks of the department head. Earlier, she seemed indifferent… Could Senpai be a tsundere like the director? But with a much stronger 'tsun' side?)
Ritsuka's thoughts wandered at the worst possible moment.
But even as she thought that, she didn't just stand still. She followed Hinako and Mash into the cave ahead.
Just as it appeared from the outside, there was absolutely no light inside the cave. Fortunately, thanks to the communication bracelets on their wrists, they could track each other's positions. As a fairy, Hinako wouldn't bump into walls as she walked.
As they moved forward, Mash kept glancing around at the dim surroundings. "This cave… was it formed naturally?"
"Overall, it seems so. But I can see traces of artificial modifications. Probably some magi discovered this natural cave and modified it to use as their workshop."
Hearing this, Hinako felt slightly uncomfortable. For a fairy born from the planet itself, the act of humans modifying their environment to suit their desires was, in a sense, equivalent to destroying her home. If only she could use Imaginary Manifestation, she'd instantly revert this place back to its original form.
The cave wasn't very long—perhaps only one to two hundred meters deep. After reaching the end and exiting the cave, a vast empty chamber stretched out before the three of them.
"So huge…"
Ritsuka couldn't help but exclaim.
It wasn't because of the cave's size itself, but because of the object inside.
Not far ahead, a large platform radiated an intense wave of mana. The faint light emitted by the dense mana almost illuminated the entire cavern.
"Is that… the mana reactor core? Is that the Greater Grail?"
"Possibly. Besides that, Mash, protect the newcomer. A troublesome opponent is coming!"
Hearing Hinako's words, Mash immediately raised her shield and positioned herself in front of Ritsuka. At the same time, she also sensed a different mana reaction amidst the thick mana filling the room.
It was the only dark red spark in the midst of deep murkiness.
*KRAK-KRAK-KRAK!*
The sound of clashing armor reached their ears. Atop the high platform, a figure calmly emerged, then leapt down and landed before them.
"Hoo~ An interesting Servant has arrived."
The figure wielding a black sword immediately fixed his gaze on Mash in the distance. And upon clearly seeing this black Saber's appearance, Mash's expression suddenly showed intense distress!
"Y-You… Miss Lia?!"
Artoria Pendragon, the blonde-haired girl Naoki had brought to Chaldea several times. Because of the Demi-Servant incident, Mash had interacted with her a few times. In her memory, she was a serious, cool, and reliable adult. Despite being a woman, she gave off an extraordinary 'knightly' impression.
But now, a black Saber with a face almost identical to hers stood before Mash.
"Lia… you know my true name, shield girl." the black Saber said, intrigued. "Yes, since you wield that shield, it's only natural you'd know my name."
"But—"
Dark mana suddenly erupted from the black Saber. A mana storm instantly spread and surged toward the ceiling!
This was just a simple release of mana, but even so, the resulting gale caused shockwaves reverberating through the cave.
Stepping forward, gripping the Holy Sword with both hands, the black Saber stared intently at Mash. "Let me see your strength, shield girl! How much power lies within that shield—let me confirm it with my own eyes!"
*BANG!*
The words weren't even finished when a loud explosion followed. The black Saber, who had been nearly a hundred meters away a moment ago, now stood right before Mash, having passed Hinako in an instant.
*CLANG!*
The Holy Sword slashed with full force, producing a loud clang as it struck the shield!
The impact sent a jolt through Mash's arm, making her wince and frown. But quickly, she braced the shield with both hands, using all her strength to stabilize her body against the force.
"Taking the first strike? Not bad, but—ugh!"
"BUGH!"
The black Saber, who had just raised his sword for a second attack, suddenly found Hinako appearing beside him and delivering a powerful punch straight to his head!
After adjusting her body mid-air and landing lightly, the black Saber looked at Hinako, who now stood in front of Mash and Ritsuka. "You are…"
"The temporary caretaker for these two little kids!"
Hinako said irritably. "I just stood right in front of you, yet you ignored me. Did you really not see me, or did you deliberately ignore me? How dare you. Though I don't feel disgusted by your act of ignoring me. After all, Servants are still considered humans, and I deeply despise humans."
"But now I can't let you ignore me. That person told me to watch over these two. So from now on, I'll fight him—Mash, from here on, just focus on protecting the newcomer. I'll handle the rest."
"Y-Yes… Wait, Miss Akuta! Why did you take off your clothes?!"
Mash had just nodded, when she suddenly realized Hinako had abruptly removed all her clothing.
"Tch, I'm just naked, right? Who isn't born naked? Can't you just get over that sense of shame?"
"Besides, I took them off because I'm afraid they'll get damaged. My fighting style is a bit… unreasonable."
As she spoke, Hinako had already removed her glasses and hair tie. Thick, dark red light surged from her slender body, and the resulting wind made her loose hair stand on end. A strange scent of blood filled the air around them.
Bathing in this blood-colored mana, Hinako felt her current body with a touch of nostalgia—how long had it been since she last let herself go like this?
"That person said I should be careful of my surroundings when using this technique. But now Mash has her shield, so I don't need to worry, right?"
"Then—feel it well, black Saber! The agony of my death!"
With Hinako's words, the mana enveloping her body instantly turned chaotic! Completely uncontrolled mana exploded like a detonated bomb. Hinako's figure within was instantly consumed by this sudden explosion!
Shielding their faces from the blast wave with the shield, Mash and Ritsuka wore expressions of disbelief—did Akuta-Senpai just die? And this… was it suicide?!
"No, no. Miss Akuta's mana hasn't disappeared. On the contrary, her activity is higher than before… It's already at the level of a manifested curse! And it's gathering above… Not good! Senpai, come here! We'll be caught in the blast!"
Understanding something, Mash quickly pulled Ritsuka toward the cave's edge!
"Eh? What are you saying, Mash?"
Ritsuka, still unable to grasp the situation, was dragged by Mash to the corner of the cave with a confused expression, then forced to crouch down.
The next second—
*BOOOOOMM!*