Seeing the crimson heart pulsing in Ritsuka's hand, Arthur suddenly clutched his own chest.
The resonance between fellow bearers of the "Dragon Factor" sent a sharp, phantom pain stabbing into his heart.
"Master?!" Arthur shouted in panic, his face pale. "What are you planning to do with that Dragon Core?! Don't tell me you're—"
Olga, hearing that term, nearly had her eyes pop out of their sockets.
"D–D–Dragon Core?!" Olga screamed hysterically. As an elite Magus, she knew exactly what that was.
"That's a pure magical reactor! Throw it away, Ritsuka! Are you trying to blow up an entire city?!"
Rikka, standing beside Olga, stared in confusion.
"Dragon Core?"
Caster narrowed his eyes, his pupils shrinking sharply as he realized Ritsuka's insane intent.
"Boy…" Caster growled. "Are you planning to violate the greatest taboo of humanity?"
Panic spread among them all.
But Ritsuka completely ignored their shouts. His focus was absolute—locked onto the heartbeat in his hand.
Slowly, he brought the blazing organ toward his own exposed left chest.
Seeing this, Caster screamed at the top of his lungs.
"DAMN IT! THAT KID HAS LOST HIS MIND! HE'S GOING TO TRANSPLANT IT INTO HIS OWN BODY!"
Caster pointed in panic. "STOP HIM BEFORE HIS BODY EXPLODES!"
Hearing that warning, Arthur and Mash didn't hesitate for even a second.
"Master, stop!"
They both lunged forward, intending to physically restrain Ritsuka's hand.
But—
CLANK!
Their steps were forcibly halted.
Dozens of matchlock rifles descended from the sky, forming a dense iron wall that blocked their path.
Behind the line of guns, Nobunaga landed slowly, her expression serious beyond dispute.
"Don't interfere," Nobu said coldly.
"Nobunaga! Are you aware of what you're doing?!" Arthur shouted, his face filled with anger and fear.
"What the Master is doing isn't just dangerous—it's suicide!"
Nobu didn't waver. She gave a thin smile, her eyes still sharp as she maintained the defense.
"Yes. I know. I know very well," she replied calmly.
"But an order is still an order."
Assassin tried to find an opening to break through, but the muzzles of Nobu's guns immediately turned toward him, forcing him to stop.
On the other side, Ritsuka was gambling with his life.
The dragon heart was only halfway embedded into his chest, yet it felt as if molten lead were being poured into his left side.
"ARGHHH… AAAAAHH!!"
Ritsuka screamed in agony. Thin smoke began to rise from his pores. His blood boiled.
Artoria, lying helplessly nearby, watched the scene with pity.
"Foolish Magus…" she hissed weakly.
"I don't know what your goal is… but implanting a magical reactor that powerful into a human body? You're only hastening your own death."
Ritsuka didn't care. With the last of his fading consciousness, he forced the heart inward with all his strength.
"GET IN… DAMN IT!"
SQUELCH.
The heart went in completely.
"GAAAAAAAHHHH!!!"
Ritsuka's final scream echoed through the cavern, shattering the silence.
It was pure suffering.
His body convulsed violently once, then—
THUD.
Ritsuka collapsed to the ground. Silence.
Seeing her Master fall, Nobu slowly dismissed her guns. Her task of holding them back was over. The outcome now lay in fate's hands.
"BROTHER!!"
Rikka screamed hysterically. With no more obstacles, she sprinted toward her brother's collapsed body. Arthur, Mash, and Olga followed immediately.
Beside Ritsuka, Artoria coughed up blood and sneered.
"I told you…"
"A normal human vessel could never withstand it. He's being destroyed from the inside."
Rikka dropped to her knees beside Ritsuka. With trembling hands, she turned his body over.
"Brother! Wake up! Brother!"
Rikka's eyes widened in horror.
Across Ritsuka's body, glowing red lines were spreading wildly from his chest to every limb—like volcanic fissures filled with magma.
His skin was unbearably hot, as if burning from within.
"Aaaarghhh…!!"
Ritsuka let out a long groan, his voice hoarse with torment. Veins bulged along his neck, and the heat radiating from his body made the surrounding air ripple.
Olga stared in horror, her hands shaking.
"You idiot! What are you actually doing?!" Olga screamed in frustration. She turned sharply toward Nobu.
"And you, Avenger! Why did you stop us?! Do you even understand the risk of this madness?! That heart will incinerate him from the inside! You're killing him!"
"Brother! Hold on! Brother!!"
Rikka screamed hysterically, tears soaking her face as she held Ritsuka's hand, which felt like burning embers.
"Move aside! I'll remove it right now!"
Caster Cú Chulainn pushed forward. His hands were already glowing with healing and separation Runes. He intended to magically cut open Ritsuka's chest and extract the Dragon Core before it was too late.
But a hand grabbed Caster's shoulder firmly.
"What are you doing?!" Caster snapped at Nobu.
"Are you going to stop his rescue too?!"
Nobu didn't answer. Her expression was serious, her eyes fixed on something above Ritsuka's body. She simply pointed upward.
"Look," Nobu said briefly.
Caster looked up—and his eyes went wide.
In the air, directly above Ritsuka's dying body, a golden object manifested from nothingness.
A Dharma Wheel with eight sword-shaped spokes.
The wheel vibrated violently, responding to its master's pain and the threat of death.
GIIIIING…
The wheel rotated once.
Clunk!
The heavy metallic sound echoed—like a death knell signaling the start of a process.
Caster was confused by the phenomenon, but he knew he didn't have time to hesitate.
"To hell with that wheel!"
Caster refocused. He pointed at Ritsuka's chest, inscribing the Runes Ansuz and Kenaz.
"Get out, Dragon Heart!"
But… nothing happened.
Caster's Runes shattered the moment they touched Ritsuka's skin.
Caster tried again by force, but the result was the same.
The heart had already fused completely with Ritsuka's flesh.
"What…?!"
Caster stumbled back a step, cold sweat dripping down his temple.
"Damn it! It can't be removed! That thing… that heart is permanently locked in!"
"Caster! Do something!" Olga screamed in panic.
"You're a Druid, aren't you?! Heal him!"
Caster shook his head weakly, his face dark.
"There's nothing I can do. That Dragon Heart is fully locked into his body. The process was too fast—this defies all medical logic."
Rikka clutched her brother's head and sobbed.
"Brother! Please hold on! Don't leave me!"
Suddenly, Ritsuka's eyelids snapped open.
The calm ocean-blue color was gone.
His eyes had turned gold, identical to Artoria Alter's.
"AAAAAAAAGHHHH!!"
The scream that tore from his throat was no longer human—mixed with a horrifying metallic scraping sound.
"Brother! What's happening to you?!"
Rikka struggled to restrain Ritsuka's violently thrashing body, as if something were about to burst out of his skin.
"Senpai!"
Mash rushed to help Rikka hold Ritsuka's arms to keep him from hurting himself.
"Calm down, Senpai!"
Clunk!
The Dharma Wheel above his head rotated again.
Each rotation brought a new wave of agony. Ritsuka's body convulsed, his bones cracking as if being forcibly reassembled.
Arthur turned his face away, unable to watch.
"Master… does he not know that dragon power is poison to humans?"
Olga bit her thumb until it bled.
"What do we do…? How do we stop this?!"
From a distance, weak but mocking laughter echoed.
"Heh… your Master really is a fool…"
Artoria Alter's hoarse voice rang out.
She lay on the ground, staring at Ritsuka with a twisted smile.
"Transplanting my heart, already tainted by the Grail's curse…? That's the same as drinking the deadliest poison in the world."
Artoria sneered, blood leaking from the corner of her mouth.
"Fine… I'll stay alive a little longer. I'll keep my life tethered so that heart remains inside him—torturing him until he goes insane."
Rikka turned sharply, pure hatred blazing in her eyes.
"YOU—!"
Caster suddenly realized something.
"Wait… that's it!" Caster shouted.
"That heart is part of a Servant's Spirit Origin! If Saber dies and disappears, then the heart inside Ritsuka will disappear as well!"
Hearing that, Rikka didn't waste a single second.
Her face went cold. Her tears stopped, replaced by killing intent.
"Assassin!" Rikka shouted loudly.
"KILL HER! NOW!"
Assassin shot forward like a shadow, blade drawn to sever Artoria's head.
But just before he reached her—
WUSH!
Two whirlwinds of flower petals—one bright pink, the other shimmering white—exploded in front of Artoria, stopping Assassin with a wall of magical wind.
"Sorry, but I can't let you kill her just yet~"
A male and female voice spoke at the same time, overlapping in strange harmony.
From within the storm of petals, two figures slowly emerged.
A man in white robes holding a wooden staff, and a beautiful woman in more revealing attire with an elegant staff.
Artoria and Arthur both widened their eyes simultaneously. Their jaws nearly dropped.
"MERLIN?!" they shouted together.
Merlin (Male) grinned broadly, flipping his hair.
"Oh? I didn't expect the male version of her to recognize me—"
He stopped mid-sentence, sensing an aura he deeply despised beside him. He turned stiffly.
Lady Avalon waved cheerfully, smiling sweetly.
"Ara~ Hello, Onii-san! I didn't expect you to show up here too!"
Merlin's face instantly turned pale with disgust. He stepped back, putting distance between them.
"You—! What are you doing here, you demonic woman?!" Merlin shouted irritably.
"Eh? Am I not allowed to be here?" Lady Avalon replied casually, glancing at Arthur.
"My dear Arthur is here too, after all."
"Stop!" Merlin yelled, covering his ears.
"Don't call me 'Big Brother' with that mouth! It's disgusting! You're giving me goosebumps!"
Lady Avalon giggled softly.
"How cruel~ We're the same soul from different worlds, you know."
Merlin let out a long sigh, shoulders slumping in resignation.
"Damn it… so you saw it too?"
Lady Avalon nodded, her expression turning slightly serious.
"Of course. It would be a waste to miss such an interesting journey, wouldn't it?"
Olga stared at the absurd interaction, her mouth hanging open.
"Merlin… the Legendary Magus… there are two of them?!" Olga muttered in shock—then snapped back to reality.
"Wait! Both of you! Do you have a way to save Ritsuka?!"
Merlin (Male) glanced at Ritsuka, noticing the Dharma Wheel spinning above his head.
CLUNK!
"Hm… looks like the process is already halfway done," Merlin muttered.
He looked sharply at Assassin and Rikka.
"Yes, I do have a way to save him. But one thing is certain—do not kill Artoria."
"Why?!" Rikka shouted angrily.
Merlin pointed at Ritsuka's chest.
"Because that heart is already locked. Thanks to the blessing of that wheel, it is no longer recognized as belonging to 'Servant Artoria'—it is now a legitimate organ of Ritsuka Fujimaru. If you kill Artoria now, the heart won't disappear, and Ritsuka will continue to suffer."
"Th-then what should we do?! Tell us how to save my brother!" Rikka cried, her voice hoarse from sobbing.
"Relax, little lady. There is a way," Lady Avalon replied lightly.
The silver-haired woman glided forward as if walking on water, stopping directly in front of Arthur. A heady floral scent emanated from her body.
Arthur tensed instantly, his hand reflexively gripping his sword hilt tighter.
"Merlin…" Arthur hissed suspiciously.
"What are you planning this time?"
Lady Avalon tilted her head, feigning surprise.
"Ara~ Your Majesty… are you still angry just because I tricked you about the number of Beasts?"
Her lips curved into a smile—beautiful, yet somehow spine-chilling.
"Don't look at me like that. I'm not planning anything evil. I just want to help our cute Master here. You don't want to lose him, do you?"
Clunk!
The sound of the Dharma Wheel rang out again—louder than before.
Arthur quickly turned toward Ritsuka.
The young man was still writhing in agony. His golden eyes burned wildly, and the red fissures across his skin deepened like flowing lava.
"Tell me," Arthur demanded.
"What will happen to the Master if we let this process continue?"
Lady Avalon flicked her staff casually.
"Oh, in terms of survival? He'll live. That strange thing above his head guarantees his body won't collapse."
Rikka let out a breath of relief.
"Thank goodness… he'll be alri—"
"But," Lady Avalon cut in sharply, her tone turning serious.
"There is a price."
She pointed at Ritsuka's glowing chest.
"The Dragon Heart he implanted is not pure. It is heavily tainted by the Black Grail's mud—containing all the evils of the world."
The atmosphere turned heavy and suffocating.
"If he wakes up like this… there's a very high chance that the Master won't be the same person anymore," Lady Avalon continued thoughtfully.
"What do you mean?" Olga asked, her face pale.
"What will he become?"
Lady Avalon stared directly into Olga's eyes.
"Ritsuka Alter… or perhaps something even worse. He'll become a cold, ruthless being without mercy. And believe me—"
She smiled crookedly.
"You won't like that version."
"Alter…?!" Mash cried, her face drained of color.
"You mean… Senpai will become like a Shadow Servant? Or like the corrupted King Artoria?"
Lady Avalon nodded lightly, her sweet smile unchanged.
"Yes. He will lose his identity and be reborn as an Enemy of Humanity. A walking disaster."
Rikka trembled violently.
"I-is there… a way to prevent it?"
"Of course there is," Lady Avalon replied easily.
She stepped closer to Arthur. Her slender fingers touched the chestplate of the King of Knights—right where his heart beat.
"The solution is simple," Lady Avalon whispered softly, venomously.
"My King… give your pure Dragon Heart to the Master."
"WHAT?!" Caster cried out in shock.
"That's insane! One Dragon Core is already killing him! Add another and his body will explode from energy overload!"
Lady Avalon turned to Caster and wagged her finger.
"No, no. Quite the opposite. Artoria's heart is 'Black' and 'Tainted'. We need Arthur's 'White' and 'Pure' heart to neutralize it. Yin and Yang balance. As a Magus of Avalon, I guarantee Ritsuka will be fine."
"B-but—" Olga tried to protest.
"Sssh. No 'buts'," Lady Avalon cut in coldly.
"Our time is limited. That wheel keeps turning."
She locked eyes with Arthur.
"You have only two choices, Your Majesty.
Give your heart now… or we kill Ritsuka this very moment before he turns into a Monster."
Lady Avalon smiled faintly, clearly savoring the dilemma.
"So… what will you choose, my magnificent King?"
All eyes turned to Arthur. Cold sweat trickled down the King's temple. His fists clenched so tightly his knuckles turned white.
In the corner, male Merlin watched his counterpart in horror, swallowing hard.
"That woman…" Merlin thought, shivering.
"She truly is a Devil. Her manipulative nature… her utter disregard for life… She really does have the potential to become a Beast far greater than I ever could."