According to historical records, "Jack the Ripper" murdered at least five prostitutes over a two-month period beginning on August 31, 1888.
Because he sent signed letters and fragments of internal organs to newspapers, he came to be regarded as the originator of "theatrical crime."
Riding on the influence of the British Empire at the height of its power, the terrifying legend of Jack the Ripper spread far and wide, making him the world's most famous serial killer.
On the other hand, he remains a figure shrouded in mystery. Aside from the bodies of his victims, he left behind no concrete evidence at all, to the point that even his race and gender could never be determined.
Yes, no one ever learned Jack the Ripper's true identity.
Not his appearance, not his real name, not whether he was male or female.
No, in the end, no one even knew whether he was human.
As a symbol of fear that threw the entire world into panic, this gender-ambiguous "he" was eventually imagined in countless forms by countless people, then recorded over and over in countless stories and academic papers.
A doctor, a teacher, an aristocrat, a prostitute, a butcher, a demon...
In fact, people could not even confirm whether Jack the Ripper was a single person. Instead, they used their fear to freely reshape his existence.
Through its spread, the story of Jack the Ripper was elevated into a "legend" with countless possibilities.
Here, Shirou proposed a "hypothesis."
In London in 1888, there were tens of thousands of prostitutes. Abortion techniques at the time were still primitive and brutal, and the children who should have been born were treated "like trash."
The infants' bodies were thrown into the rivers flowing through the East End where the prostitutes lived, and their resentment gradually accumulated and settled in the murky water.
The resentment of tens of thousands of infants, rejected before they were ever born, slowly took on human form and appeared as a young girl.
She wandered the East End without understanding why she had been born, why she was sad, or why she felt so cold. She knew nothing at all.
And yet, even though she knew nothing, she clearly understood that she wanted something.
Unable to hold herself back, the girl called out "Mama" to a passing woman, only to be cursed at in return.
The girl was so hurt that she killed the woman. It was an instinctive impulse born from the obsession of "never having been properly born."
Driven by the wish to "return to her mother's womb," the girl dismembered her victim.
Then she killed others.
Before long, people had given her the name "Jack the Ripper."
After she killed several prostitutes, a certain Magus realized that this string of grotesque murders was the work of a demonic entity, and quickly dealt with her.
Just like that, the world's most famous serial killer vanished carelessly into the darkness of history.
This is not the correct history. At best, it is only a "hypothesis."
For every rumor about Jack the Ripper, another facet is born.
And in this Holy Grail War, Jack the Ripper, summoned as the Assassin of "Black," is a conglomeration of resentment, a malevolent spirit temporarily manifesting in the form of a young girl, born from the countless stillborn fetuses abandoned in Whitechapel.
"This is Jack the Ripper's true form."
Shirou finished his explanation and looked at the woman clenching her hands.
"Reika-san, now that you know this little brat is nothing more than a malevolent spirit, do you still want to be her mother?"
Reika Rikudou's resolute expression did not waver.
Seeing that, Jack the Ripper happily threw herself into the woman's arms, nuzzling her head against her and acting spoiled.
Well... Shirou had guessed this would be the result from the start.
He smiled and teased her. "Servants are already spiritual beings to begin with, but madam... your child is especially troublesome by nature."
"Please don't joke about Jack." Reika Rikudou glared sharply at the boy.
After hearing Jack's background from Shirou, her love and pity for the girl had only deepened.
She would never let Jack be alone again!
Reika Rikudou clenched her fist and silently swore it to herself.
"Then let's begin," Shirou urged.
The woman nodded, then looked at the Command Spell on the back of her hand.
"Mommy...!"
Jack the Ripper looked uneasy, and Reika Rikudou answered her with a reassuring gaze.
"By the power of the Command Spell, Assassin, take physical form!"
In that instant, Jack the Ripper's meager remaining Mana swelled explosively.
That was the result of using all three Command Spells at once.
Command Spells are enormous crystallizations of Mana far beyond what any Magus could normally store, capable of producing effects bordering on Magic.
For example, allowing Jack the Ripper, who was originally a malevolent spirit, to take physical form.
Ordinary Heroic Spirits could not accomplish such a thing, but Jack the Ripper was an anomaly even among Servants.
A girl who had possessed no body in life and had never truly been born was now undergoing the act of "being reborn into this world."
The Mana that formed her temporary body rapidly transformed into another form of life, and the Spirit Core that housed the concept of the Heroic Spirit changed into a beating heart.
"Ugh, uuuuuugh... Mommy!"
Just as Shirou and Reika Rikudou both thought the plan had succeeded, Jack the Ripper suddenly let out a scream of agony.
"What's wrong, Jack?"
Reika Rikudou hurried over to the fallen Assassin.
"It hurts! Mommy! It hurts! What is this...? It hurts so much!"
Jack the Ripper's small, slender body thrashed wildly on the floor as she screamed in pain.
"Mommy... it hurts! No! I hate it! Aaaaaah!"
"Shirou-kun! Please help her! Save Jack!"
Reika Rikudou picked up the girl and carried her to the boy, but he calmly shook his head.
She bit her lip, held Jack the Ripper close, and stroked her back.
Right now, she and her daughter had no choice but to trust this boy.
After a while, Jack the Ripper's condition gradually stabilized.
"She's fine now."
Shirou took the girl from the woman's arms, examined her, and said so.
"Really... she's all right?"
"Mm."
Hearing Shirou say that, Reika Rikudou's heart finally settled.
The strength left her legs, and she sank to the floor.
"By the way... you should probably put your clothes back on," Shirou said, turning his face away.
Only then did Reika Rikudou realize she was still dressed in the revealing outfit she had used to seduce the boy.
"I-I'm sorry..."
The woman awkwardly pulled her coat back on.
Shirou carried the unconscious silver-haired girl back to the sofa, then explained the necessary precautions to Reika Rikudou.
Although Jack the Ripper had obtained a physical body, she still could not be considered a true human. She was an "Incarnated Servant."
From now on, she would still need to take in Mana to maintain normal life functions.
"Eating can replenish a little Mana, but it still won't be enough.
If this keeps up, the little brat will grow weaker and weaker. If only there were a Magus who could supply her with Mana..."
"I'll learn! I'll study Magecraft for Jack's sake!"
"You can't become a Magus through effort alone... No, wait."
Shirou remembered Reika Rikudou's miraculous experience of Summoning a Servant on the brink of death, and how she had just used three Command Spells to successfully allow Jack the Ripper to take physical form.
That was absolutely not something just anyone could do.
In truth, Shirou had believed the plan had only a thirty-percent chance of success, and he had been prepared to ignore Reika Rikudou's objections and eliminate Jack the Ripper if she completely broke down.
But Reika Rikudou had succeeded.
He could not be certain, but Reika Rikudou might truly have the talent of a Magus.
"I'll introduce you to a teacher who can help you study Magecraft," Shirou said after thinking it over.
"Thank you very much," Reika Rikudou said, bowing her head in gratitude.
"Would you be willing to take the little brat to London?"
After Shirou explained that London, England, was the center of modern Magecraft, the woman looked slightly hesitant.
For Jack the Ripper, London was both her Birthplace and a place like hell.
"Um, I know this sounds ungrateful after all you've done for us, but if possible..."
"You don't want to go to London, right?"
Shirou nodded. "Okay, then go back to Japan. Go to Fuyuki and find someone named Rin Tohsaka..."
"Japan, too..."
Reika Rikudou said timidly, "If possible, I'd like to take Jack somewhere new and start over."
Shirou was a little speechless. This woman... she was even more willful than he had expected. As expected of a young lady from a fallen household.
Well, no helping it. He might as well see this through to the end.
Shirou told Reika Rikudou to bring him a piece of paper, then wrote a long name on it.
"Luviagelita Edelfelt."
"Go to Finland and find this person."
Shirou handed the note to Reika Rikudou.
"Excuse me, is this lady... someone you know, Shirou-kun?"
"I don't know her."
"Huh?"
"To be precise, I don't know the Luvia of this world... Never mind. Don't worry about it."
The face of that haughty, beautiful young woman surfaced in Shirou's mind, and he said, "Anyway, this woman is rich and loves sticking her nose into other people's business.
As long as you ask her for help, she'll magnanimously take you in. I can guarantee that."
"O-okay."
Reika Rikudou gratefully tucked the note away.
"All right, I've said everything I need to say. It's about time you two left."
"Huh? So soon?"
"Yeah. Leave tonight. Staying here any longer will only make trouble for me."
Shirou's attitude cooled completely from his earlier helpfulness. "If Ruler finds out about what happened tonight, I'm finished."
"I understand. Thank you again."
Reika Rikudou bowed deeply, while Shirou sank into the sofa and waved her off impatiently.
"Um... may I ask one last question, Shirou-kun?"
"No. Hurry up and take the brat with you. Get out!"
"Why are you helping us this much? You could have just left us alone."
Reika Rikudou stared hard at Shirou.
It seemed she would not let this go unless he answered.
"Isn't it obvious?"
Shirou looked at Jack, who was sleeping peacefully with a happy expression. "You know this is wrong, but you're still determined to bear that sin. Not for anything else. Just for this brat."
If it meant granting Jack's wish, Reika Rikudou probably would not hesitate even if she had to become a demon.
Shirou did not think that was the "right" way for a person to live.
If "heroes of justice" existed in this world, then she and her daughter would undoubtedly be judged as villains.
Everyone would say so.
Even so...
"Even if all of humanity, every last person, condemned you as wrong, you would still risk your life without hesitation for the one precious thing in your heart.
I admire that about you, Reika-san."
As Shirou stroked Jack's head, he heard the woman draw in a breath.
She smiled from the bottom of her heart. "Shirou-kun, you really are a strange person... hehe."
At this point, Shirou felt as though he finally understood why Manaka Sajyou had summoned him.
His Master and Reika Rikudou really were alike in certain ways.
With their faint sense of morality, they could commit any outrageous act, any evil deed, for the sake of the ones they cherished.
Shirou sighed and patted the girl's cheek. "Hey, brat, wake up! Get up already!"
Jack the Ripper opened her eyes, then immediately tried to cling to Shirou again, only for him to push her away with a look of disgust.
"Thank you so very much."
Reika Rikudou took Jack's hand, ready to follow Shirou's instructions and leave this troublesome place tonight.
"All right, all right, hurry up and go."
"I will never forget this kindness. One day, I'll repay you."
"I doubt you'll get the chance."
Reika Rikudou shook her head and said firmly, "No. This child and I will definitely repay you... Come on, Jack. You say it too."
"Mm! Thank you so much, big brother! You made Mommy smile! Bye-bye~~!"
And so, Reika Rikudou happily left with her daughter.
"Her daughter, huh..."
Standing by the third-floor window, Shirou watched the mother and daughter disappear into the night, and a sudden melancholy came over him.
In truth, when Reika Rikudou had asked why he was helping them, Shirou had not given her the full reason.
Aside from admiring her resolve to protect Jack at all costs, there was another reason.
Shirou simply could not bring himself to abandon that pitiful, tragic mother and daughter.
"I wonder if this is the influence of this Spirit Origin."
"Come to think of it, I remember King Arthur (Artoria) had a child too. That was..."
Just then, there came a knock from behind him.
"Knock, knock, knock, knock, knock." It was extremely urgent.
Shirou closed the window, walked to the entrance, and reached for the doorknob.
The next second, the door suddenly exploded, shattering into countless fragments.
Wooden splinters shot toward Shirou like shrapnel from a Claymore landmine, but he had already been prepared. He took a casual step back and avoided the ambush.
When he heard that Jack the Ripper had fled after fighting a Servant, Shirou had already considered the possibility that someone might track her here.
That was why he had been so impatient to make Reika Rikudou leave as soon as possible.
According to the brat, the one who fought her tonight was the "Red" Saber.
"All right! Finally caught you! Die, Assassin!"
Mordred laughed loudly as she swung her magic sword at the target behind the door.
At this distance, the Knight of Rebellion was confident she could finish off a mere Assassin in a single blow.
I failed to finish off Archer last time, but this time, I won't make the same mistake agai...
"!?"
The moment Mordred saw her enemy's face clearly, her eyes widened, and the magic sword she had swung with all her strength froze in midair.
Fa... ther...!?!?
Shirou had no idea why she had stopped attacking, but he had no intention of letting the opportunity slip away.
"Strike…"
The red-haired boy's expression did not change as he gripped the wildly surging storm of Mana with both hands.
"W-wait... wait a second, aaaaaah!"
The "Red" Saber shouted in panic, but Shirou had no reason to trust a despicable enemy who had ambushed him from behind a door.
"...Airrrrrrrr!"
The gale wrapped around Excalibur was compressed and condensed to its limit in an instant, then released together with a golden light.
This was the advanced technique of the "Invisible Air Barrier," "Strike Air."
"Guh...!?"
The "Red" Saber raised her magic sword as if facing a mortal threat, while equipping her helmet at the same time.
But before that overwhelming destructive power, defending was completely pointless.
Mordred was struck in the chin by a blow launched from below, sending her flying like a cannonball with force comparable to a "Mana Burst."
"Gah... hah!"
The "Red" Saber's head slammed into the ceiling first, then she crashed heavily back to the floor.
The helmet she had equipped in a hurry was destroyed by the attack and shattered into pieces.
Mordred lay spread-eagled on the floor, eyes rolled back as she passed out.