"Y-you…" the Jewel Magician's voice sounded heavy. "You're serious about doing this? You intend to implant that thing into your human body?"
Ritsuka nodded firmly. "I'm serious, Sensei. With my adaptation ability… is it possible?"
Silence followed. Zelretch stared intently at his disciple, searching for hesitation—but found none.
Suddenly, booming laughter erupted from the mass of water.
"Hahahahaha! HAHAHAHA!"
Zelretch laughed like a madman. "Magnificent! You've truly gone insane, Ritsuka! Trying to fuse human flesh with something like that? That is blasphemy against Mystery itself!"
"For the sake of protecting those who are precious to me," Ritsuka cut in coldly. "I'll become a monster if I have to."
Zelretch's laughter subsided, replaced by a feral grin.
"Theoretically… with that absurd adaptive anomaly of yours, it might be possible. But listen carefully, boy. The pain won't be like an ant bite. It'll feel as if you're swallowing the sun alive. Your blood will boil, your bones will melt—and that thing is already tainted."
"I'm ready to pay the price," Ritsuka replied without blinking.
"Well, you really are crazy," Zelretch muttered, shaking his head.
Suddenly, Zelretch fell silent, as if thinking deeply about something.
"But… why go through the trouble of hunting the Tainted King in that cave?"
"What do you mean, Sensei?"
"You have fresher, purer material right in front of your eyes," Zelretch whispered, his voice dripping with demonic temptation. "Arthur Pendragon. You could use him instead—and the quality might even be better."
Ritsuka froze, his eyes widening.
"Just use a single Command Spell," Zelretch continued casually. "Simply order him to tear—"
"SENSEI!!"
Ritsuka's shout cut him off sharply. His breathing was ragged, his eyes glaring fiercely at the mass of water.
"Never… never finish that sentence," Ritsuka growled.
He glanced briefly toward Arthur, who was smiling in the distance while talking with Caster.
"He is my friend. He is a knight who fights to save the world. I will never—never—defile his knightly path with such vile betrayal!"
Zelretch let out a long sigh.
"Hah… You're still too soft, boy. Far too naive for a Magus."
Ritsuka didn't argue. He simply offered a thin smile—one filled with unwavering conviction.
"Alright, alright. This old man gives up," Zelretch said, waving his hand in resignation. "Do as you please. Carry out your insane plan. I'll be watching."
"Thank you, Sensei," Ritsuka said sincerely.
Without wasting another moment, Ritsuka cut the connection with Zelretch and leapt down from the building, dashing toward the crater where his Servants had gathered.
After Ritsuka left, the water's surface rippled again. But this time, it wasn't Zelretch's heavy voice that dominated.
Another voice—a cheerful, playful childlike voice—suddenly slipped into the communication channel.
"Hee~ What an interesting plan…"
The reflection in the water twisted.
"So the answer is already clear, isn't it?"
The voice giggled gleefully.
"Are you strong because you can adapt?
Or is adaptation strong because it has you?"
---
Ritsuka landed smoothly on the ground and walked toward his group, checking everyone's condition.
"You two alright?" he asked Rikka and Olga.
Olga let out a breath, looking a bit disheveled but relieved. "Hmph. Thankfully, Assassin worked fast retrieving us. So we didn't have to deal with those damn skeleton monsters."
Rikka stepped closer, her eyes fixed sharply on the volcanic mountain in the distance. "Brother, are we heading straight for the enemy base now?"
Ritsuka nodded firmly. "Yes. We'll end this nightmare as quickly as possible."
His gaze then shifted to the silver-armored knight standing slightly apart.
"Arthur," Ritsuka called. "Did Caster explain the situation to you?"
Arthur turned around. His handsome face looked somber.
"Yes, Master. Caster told me everything. About this city… and about who the 'King' ruling that cave is."
Arthur fell silent for a moment, his hand clenching tightly around his sword's hilt.
"Our final enemy… is another 'me.'"
Ritsuka looked at Arthur's guilt-filled expression.
"Don't blame yourself. The one committing these atrocities isn't you. She's merely a lost shadow—a distorted side swallowed by darkness."
Arthur slowly shook his head, his eyes vacant as he gazed at the never-ending flames of Fuyuki.
"I understand that, Master. But still… it hurts," he admitted softly.
"The Holy Sword that should protect life and bring hope… is now being used to destroy and burn everything. That is a desecration of our oath."
Ritsuka stepped forward until he stood directly in front of Arthur. Without hesitation, he raised his hand and lightly knocked on the chest plate of Arthur's armor.
Tap.
Arthur flinched slightly, looking at his Master.
"That's precisely why we're here, Arthur," Ritsuka said, his eyes burning with resolve. "We fight to correct that mistake. We fight to restore the meaning of 'protector' and 'hope' to that sword."
Ritsuka smiled confidently.
"And for that, I need your strength. Your strength—Arthur Pendragon, who stands before me. So lend me your sword."
Hearing this, the doubt in Arthur's eyes vanished. He straightened, once again radiating the aura of a majestic king.
"Understood," Arthur replied firmly. "As you wish, Master. My sword is yours. Let us save this world."
Ritsuka smiled with confidence. He turned to face his team and clenched his fist into the air.
"Let's go. The final battle is waiting for us there," Ritsuka said, pointing toward Mount Enzou looming darkly in the distance.
"WAHAHAHA!" Nobu's laughter boomed, shattering the night's silence.
"At last! The bastard who dared to trample my land will finally meet his end!" she roared with a wide grin. "I'll make sure he pays for his sins in flames!"
The group began ascending the mountain path.
Olga Marie walked beside Ritsuka, glancing toward Arthur.
"It's still hard to believe you managed to summon a male King Arthur using just that crater," Olga muttered in awe.
"But… theoretically, victory is already in our hands. Facing a corrupted Black Saber with a pure King Arthur—this is the perfect counter."
Behind them, Caster Cú Chulainn kept staring at Arthur with an odd look, examining him from head to toe with narrowed eyes.
Arthur, feeling the gaze, finally turned, slightly uncomfortable. He tilted his head politely.
"Caster? Is something the matter? Is there something wrong with my appearance?"
Caster leaned closer, studying Arthur's features closely while stroking his own chin.
"No… I'm just surprised," Caster said honestly. "I never expected the male version of the King of Knights to look like this."
"What do you mean?"
"Your face," Caster pointed. "It's exactly the same mold as the female version I know. You're quite handsome, Your Majesty."
Nobu, overhearing this, chimed in casually while shouldering her rifle.
"Well, of course! You're the same person from different worlds. If your faces were completely different, that would be weird. You probably have another version of yourself somewhere with the exact same face too."
"No… it's not just the face," Caster objected, narrowing his eyes again as if appraising an antique. "Your aura is different."
Arthur grew increasingly uncomfortable under such scrutiny and slightly turned his face away.
"Caster, could you stop staring at me like that? It's… somewhat impolite."
Caster chuckled, scratching the back of his head. "Ah, sorry, sorry. I was just thinking… you feel more 'human' and open as a king."
Caster grinned. "Compared to your female counterpart who's stiff like an ice statue, you've got far more approachable leadership charisma."
Hearing that, Mash suddenly furrowed her brow. A sense of offense rose inexplicably in her chest.
"Caster, that was extremely rude!" Mash snapped sharply.
"King Artoria may appear strict, but she is still a great and compassionate King of Knights!"
The atmosphere fell silent. Caster stopped walking and stared at Mash with a sharp, probing gaze.
"Hoo…" Caster tilted his head. "I was just being honest. But, Ojou-chan…"
"Where did you learn the name 'Artoria'? If I recall correctly, I've never mentioned Black Saber's true name in front of you."
Mash froze mid-step. Her eyes widened in confusion.
"Eh…?"
She touched her lips, her face turning pale.
"W-why…?" she murmured. "That's true… why do I know her name is Artoria?"
Ritsuka, hearing the exchange behind him, glanced briefly at Mash's shield.
"Resonance…" Ritsuka thought.
"It seems Arthur's presence is triggering the Heroic Spirit's memories within Mash faster than I expected. Is Galahad reacting to his King…?"
He hesitated.
"Should I tell her now…?"
Rikka, walking beside him, noticed the change in her brother's expression and lightly nudged his arm.
"Brother? You spacing out? What are you thinking about?"
Ritsuka snapped back to reality and quickly shifted to a casual expression. He reached out and patted Rikka's head.
"Hmm… nothing," Ritsuka deflected. "Rather than worrying about that, you should prepare yourself. Once this Singularity is over, I'm going to train you relentlessly."
Rikka's eyes widened in horror.
"WHAT?! Training?!" She stepped back, her face pale. "No way! Your training would be hell! All my bones would break!"
She clung to Ritsuka's arm, putting on a pitiful expression.
"Mercy, Brother… I'm your cute little sister! You wouldn't torture me, right?"
Ritsuka looked at her flatly, then played his trump card.
"Don't be spoiled. If you refuse…" he counted on his fingers.
"One, I won't buy you gifts anymore. Two, you're banned from ever stepping into my apartment. And three…"
Ritsuka flashed a devilish grin.
"I'll tell Uncle and Aunt exactly how much allowance you spent on gacha last month. Understand?"
"KYAaa!!!" Rikka screamed in panic. "NO!!! NOT THAT!!"
She nearly burst into tears.
"You're evil! A demon! How could you threaten your own sister with gacha shame?!"
Ritsuka patted her head again—this time gently but firmly.
"Precisely because you're my sister, I have to train you. This world is dangerous, Rikka. I won't let you remain weak."
"Hic… you're mean…" Rikka sniffled, pouting.
They continued toward the mountain, Rikka's small complaints easing the tension before the final battle.
---
Deep within the damp cave lay a massive opening leading to the Mountain's Core. At its center, a pillar of dark crimson light towered upward, piercing the cavern ceiling.
And standing before that pillar was a female knight clad in jet-black armor, radiating dense darkness.
Slowly, the knight opened her eyes.
A pair of cold golden-yellow eyes gazed at their arrival without emotion.
"So… you finally made it,"
her voice was flat, yet echoed with terrifying authority.
Mash, standing at the front line, immediately read the enemy data through her shield.
"Massive-scale Mana reaction confirmed! With energy density at this level… it's certain. She is King Arthur!"
Rikka, who had mustered the courage to stand beside Mash, swallowed hard. Her body trembled violently. She wasn't a Magus, but her instincts screamed danger.
"Is… is that another version of Arthur?" Rikka thought in panic.
"So she really is a woman…?"
But her curiosity was quickly swallowed by terror.
"No… more importantly, this pressure," Rikka clutched her clothes, struggling to breathe.
"Even from this distance, it feels like my lungs will burst. Her energy pressure… it's far greater than Berserker's!"
Saber Alter glanced at them briefly, then snorted dismissively.
"Good. Let's get this over with."
BOOM!
The ground beneath her feet cracked instantly.
The black knight lunged forward at an absurd speed. Strangely, she didn't aim her sword at Mash or Rikka. Her gaze was locked onto the darkness beside Rikka.
She was targeting the other "King" hiding there.
At the same moment, a shadow shot out from the darkness beside Rikka to meet the attack.