"So you do remember..."
Shirou narrowed his eyes.
The moment he spoke the name "Baobhan Sith," Avanger's pupils widened.
"Baobhan Sith... the Baobhan Sith everyone loved... no... the Baobhan Sith who was always smiling... I am..."
The red-haired girl's mental state suddenly became dangerously unstable. She curled in on herself and began muttering under her breath.
Just as Shirou was about to press her further,
"No... no, that's not me... that's not me... ugh...!"
Avanger suddenly erupted with unbelievable strength, violently shoving Shirou away before clutching her head in both hands.
Shirou had already pushed his body to its limit from using "Time Alter. Hexagon Accel" earlier, but fortunately, Lady Avalon caught him from behind.
"Are you alright, Master?"
"Yeah, I'm fine."
After thanking Lady Avalon, Shirou looked at Avanger again.
"...Baobhan Sith of the villagers... miserable and sorrowful Baobhan Sith... Vampire Baobhan Sith..."
"I am the Fairy Knight... the Fairy Knight... Tristan..."
"I'm sorry... Mother... I messed it up again... forgive me... I'm sorry..."
Mother?
Shirou frowned slightly. "Avalon-nee-san, keep an eye on her... I'm going over there to check what's happening."
For now, he had no choice but to put aside the red-haired girl who seemed to be Baobhan Sith. The top priority was dealing with the Holy Grail that had already manifested.
Trace on.
The incantation echoed in his mind, and the Blades of Chaos appeared in his hands.
"No. You must not destroy the Greater Grail."
Just as Shirou was about to smash the Holy Grail apart, a voice came from behind him.
Black Artoria walked up to his side.
As expected of the true Red Dragon, she had completely recovered from critical injuries in barely a minute.
Shirou frowned. "Why do you say that?"
Saber Alter looked up at the golden cup hanging in the night sky and explained,
"That thing is not 'floating' in midair. It merely 'exists' there.
"It is a 'Gate' connected to the main body, the Greater Grail buried deep beneath Mount Enzou, west of Miyama Town."
"For the past sixty years, the Greater Grail has been continuously absorbing the Great Source of Mana from the leylines. Now, after receiving the souls of five Heroic Spirits, its interior is overflowing with a vast vortex of Mana."
"And inside it, there is also the... 'curse accumulated over more than ten thousand years' that Avenger brought from another world."
"!!"
Shirou turned to look at the red-haired girl, and Saber Alter continued.
"If you destroy the 'Gate' now, the black sludge inside will come pouring down through the forced opening.
"Until that opening closes completely, you will have no way to stop the black mud from spilling out from the other side."
After hearing that, Shirou fell silent.
So I can't just destroy the Holy Grail... Should I trust Saber Alter?
Just a minute ago, she had been obsessively trying to obtain the already corrupted Holy Grail, and now she was suddenly helping him.
Shirou met Saber Alter's gaze, then smiled.
"This information... you learned it after being contaminated by the substance inside, didn't you?"
"Ah." Saber Alter gave a blank nod. "That's right."
"I understand."
Shirou nodded and chose to believe her.
"Then what should I do, Saber...san?"
Black Artoria felt completely different from the Artoria Shirou loved most. She gave off a cold, untouchable air of superiority, so he ended up adding an honorific at the last moment.
"What happens if we leave it alone?"
"Even if you do nothing, the thing inside will break out on the seventh night and burn everything on the surface to ashes."
Saber Alter spoke calmly.
"But Shirou, you didn't kill me just now... that seems to have been the right choice."
"If my soul had also returned to the Greater Grail, what is inside probably would not have lasted even until tonight."
"Since the Grail's end can no longer be prevented, the best thing to do now is flee as quickly as possible…"
"As long as you leave this city, the corruption of the Greater Grail will at least no longer threaten you..."
Then she saw Shirou smiling at her.
The moment she saw that expression, Saber Alter understood. There was no way Shirou would ever abandon people and run.
"Saber, take Irisviel and get out of here. I'm staying to deal with the Holy Grail."
"Deal with it? How?"
Saber Alter frowned slightly. No matter how capable Shirou was, that was not something he should be able to handle.
Shirou answered,
"I'm going to use my 'Fairy Domain' to contain the black substance inside the Greater Grail."
"Didn't you just say it yourself? Fortunately, the Greater Grail has only collected the souls of five Servants so far... so there's a chance it might work."
Saber Alter's expression darkened.
"...That's too reckless, Shirou."
"The black sludge of the Grail will erode your Magic Circuits, and your mind will be affected as well. In the worst case..."
Shirou smiled lightly.
"In the worst case, I'll turn into an Alter like Saber."
"Honestly, that doesn't sound so bad. It actually sounds pretty cool."
"Serious and cute Artoria is amazing, but lately I'm starting to appreciate the charm of cold and domineering Artoria too."
"...Shirou!"
Saber Alter frowned in displeasure, but the boy had already made up his mind.
"I told you from the start, didn't I? I entered this war to stop the Holy Grail from doing evil."
Saber Alter still hesitated.
"That is true, but..."
"...There's no need for that."
Shirou and Saber Alter turned at the same time and found Avanger strolling leisurely toward them.
It seemed she had already recovered from the confusion caused by regaining her memories.
"...Stop there. Don't come any closer."
Saber Alter stepped in front of Shirou, her face full of caution.
Shirou was a little happy to see Saber Alter standing on his side, but he still felt he should tell her.
"It's alright now, Saber."
The boy noticed that the hostility had vanished from Avanger.
He did not know why, but she no longer seemed to have any intention of continuing the fight.
"Huh? What's with you?"
The red-haired fairy girl looked Black Saber Alter up and down as she stood in front of her.
"Just a moment ago, you were my Servant, and now you're already sucking up to that little brat?
"You really can spread your legs for anyone without a second thought, huh... you slut! Hahaha, that's hilarious!"
Avenger clutched her stomach and burst into laughter.
Veins twitched on Saber Alter's forehead. ".........."
Scorching Mana erupted from her body, and a heatwave swept through the entire Ryuudou Temple. Shirou quickly grabbed Saber Alter by the wrist.
"So you're back to your senses now, Avenger?"
Shirou spoke up.
There was a lot he wanted to ask, but this was clearly not the time for it.
The red-haired girl shot him a glance. "Hah? Are you stupid? I've been perfectly clear-headed the whole time."
Shirou. ".........."
Her hostility was gone, but her mouth was still just as vicious as ever.
With a personality this awful, is she really my Baobhan Sith?
"Avenger, are you willing to help us?" Lady Avalon asked.
"Hmph."
The red-haired fairy gave no direct answer and crossed her arms over her chest.
"There actually is a way to neutralize the Holy Grail, you know?"
Shirou quickly asked, "What do we need to do?"
Avenger stared at the Greater Grail and rolled her eyes.
"You know perfectly well, don't you... as long as you kill me, every problem will solve itself."
Using her authority over the Holy Grail, Avenger had taken Irisviel's place as the "Key."
So as long as she disappeared, the manifestation of the Holy Grail would be forcibly cut off.
It would not be a fundamental solution, but at the very least, it could delay the Grail's completion for several years, maybe even ten.
And during those ten years, Shirou would continue to grow as a Magus, giving him plenty of chances to dismantle the Greater Grail.
Of course, Shirou had realized that method too, but...
"I can't stand this shitty place for another second. I'm going back right now."
The red-haired fairy waved her hand impatiently.
"Hey, Avenger..."
Shirou stopped halfway through the sentence. Before he knew it, Avenger was already standing beneath the Holy Grail with her back to them.
At that instant, a deeply ominous premonition surged through his intuition.
The red-haired fairy looked back over her shoulder and spoke as if it were nothing serious at all.
"That thing is something I brought here, so I'll be the one taking it away. You can just stand there and watch."
As she spoke, she raised her graceful arm, then,
"Wait!"
Ignoring Shirou's shout, the girl thrust her hand into her own chest and tore out her beating heart.
"Ahahahaha, just as expected of me... like a ruby... so beautiful♡"
The fairy girl smiled in intoxicated delight, blood splashing across her delicate face and extravagant dress.
After spinning in place a few times with her own heart in hand, she began to collapse. Before she could hit the ground, Shirou rushed forward and caught her in his arms.
"Baobhan Sith!"
Shirou knew for certain now. She was Baobhan Sith.
No matter how nasty her personality had become, no matter how cruel her words were, the very last trace of kindness still remained in her heart.
Once she realized the evil she had committed, she decisively chose to end this chain of cause and effect with her own life.
She was the girl Shirou knew.
Regret welled up inside him. Why had he not realized it sooner?
He looked down and saw that her feet had already vanished.
Avenger was disappearing little by little.
With her Spirit Core crushed in her own grasp, she could no longer maintain her physical body.
"Hang in there, Baobhan Sith!"
"You're so damn loud... at a time like this... can't you be quiet for once..."
Lying in Shirou's arms, the red-haired girl weakly opened her eyes and gave him a mocking smile.
"Quit calling me that so fondly... do I even know you...
"Hey, little brat... answer me this... why do you have a black Holy Sword...?"
"It was a gift from someone important to me."
"..........Someone important."
In her haze, the girl recalled something her mother had told her long ago.
The boy who possesses the "Pitch-Black Holy Sword" and the "Sword of Infinity"...
He is Arthur, the founding king of Fairy Britain... and my mother's husband.
Was all of this... really just a coincidence?
The red-haired fairy placed her hand against the boy's cheek.
So warm...
It felt strangely familiar...
"What's your name...?"
Shirou took her hand in his and answered,
"Shirou. My name is Shirou."
"Shirou... mm... I'll remember it."
Avenger narrowed her eyes and murmured softly.
"...It's time.
"I'd like to say we probably won't meet again, but... somehow, I feel like we will."
With those words, the girl dissolved into light and vanished.
And just like that, the crisis of the Greater Grail was resolved through the self-sacrifice of an unnamed girl.
The Fourth Holy Grail War came to an end in utter chaos.
"..."
Shirou stared blankly at his empty arms for a moment, then silently rose to his feet.
Before he could steady himself, a wave of dizziness hit him.
All the fatigue he had built up until now came crashing over him like a flood, and his body pitched forward uncontrollably.
"Shirou!" "Master!"
Just before losing consciousness, he heard the panicked voices of Saber and Lady Avalon.
...
...
When he opened his eyes, he was greeted by a familiar ceiling.
"Ah, you're awake!"
A lively girl's voice rang out by his ear.
Struggling to turn his head, he saw the face of his "colleague."
She, Fairy Knight Tristan, looked thoroughly displeased.
"Why are you in my room?"
At that, the girl standing by the bedside, Fairy Knight Lancelot, snapped back indignantly,
"Is that how you talk to your savior?"
"My savior...?" Fairy Knight Tristan frowned slightly.
At that point, the other woman beside the bed, Fairy Knight Gawain, spoke up to explain.
"Tristan, you fell out the window of your room... and into the giant cavern behind Camelot."
Fairy Knight Tristan stared at her in stunned disbelief.
"What did you just say?"
The giant cavern at the very center of Britain.
On the northern side of that cavern stood the walls built as though to guard it. Those walls were the present royal capital, Camelot.
In the legends of the Fairy Kingdom, the giant cavern was a place where everything useless was thrown away.
As Queen Morgan's heir, she knew part of the truth.
More than ten thousand years of curses had accumulated there, and sleeping within it was a planetary-scale calamity, the cursed god Cernunnos.
...I fell into a place like that?
"That's right, that's right."
Fairy Knight Lancelot puffed out her chest proudly.
"I'm the one who hauled you up from the very bottom of the giant cavern, you know? Hurry up and thank me!"
Fairy Knight Tristan ignored her and turned to Gawain instead.
"How long was I asleep?"
Gawain tilted her head, thought for a moment, and replied,
"About two weeks, I think? Her Majesty Morgan came to see you once during that time.
"She seemed to decide that you were fine, so she left again pretty quickly."
"Mother..."
Tristan held her chin and fell into thought.
At that moment, Gawain and Lancelot got to their feet and started toward the door.
"Get some proper rest, Tristan. I'll go inform Her Majesty Morgan."
Tristan called out to the two of them before they could leave.
She spoke the name of the person she had met in her dream.
"Shirou... do either of you know that name?"
".........."
Gawain and Lancelot exchanged doubtful looks.
After a brief hesitation, Lancelot was the one who answered.
"That was the name our King used when he was human."