From the moment he was born, Kurokami Gen had suffered from a terrifying, incurable illness.
Congenital insensitivity to pain (CIP)—a hereditary sensory and autonomic neuropathy (HSAN).
Worldwide, fewer than forty confirmed patients were estimated to exist. Because the neural pathways responsible for transmitting pain signals were blocked, sufferers completely lost the ability to perceive pain.
Pain was one of the body's most vital alarm systems.
Because humans feared pain, they avoided harming themselves. Because they felt pain, they realized when their bodies were being damaged and could react in time to avoid danger.
That was pain's dual-layered protection mechanism.
A living system with complex regulatory functions was never meant to exist without pain. Most patients with CIP severely injured themselves in childhood and never made it to adulthood.
Gen gave a self-mocking smile.
I'm not like Fujino Asagami. From the moment I was born, this was my fate.
In Kara no Kyoukai, Fujino lost her sense of pain due to her senses being artificially sealed. She couldn't even realize her appendicitis was worsening.
That series had been Gen's gateway into otaku culture—the first time he'd truly empathized with an anime character.
When he later watched Redo of Healer, he found himself envying the protagonist instead—the revenge-twisted healer who could experience the pain of others. He had longed for an ability like that.
And then—
A miracle happened.
"According to the latest research, this disease stems from incomplete ectoderm development during embryogenesis. There are five known subtypes. In Type II congenital insensitivity to pain, many affected families show mutations in the FAM134B gene on chromosome 5…"
Before the frog-faced doctor could finish, Gen had already read every scrap of knowledge from his mind.
A mutation in the FAM134B gene prevented proper protein expression, leading to apoptosis of dorsal root ganglion neurons and blocking pain perception.
So… he already had a treatment plan.
"I suspect Kurokami-kun is most likely Type II, but we'll need genetic testing to confirm. Even if we repair the chromosome via gene modification, the neurons that have already undergone apoptosis cannot regenerate. We could consider cloning neurons and performing a cellular-level transplant…"
"Thank you for your concern, Sensei." Gen smiled lightly. "I stopped expecting a cure a long time ago. For me, the cost and risks are a bit too high."
The illness was like a curse written into destiny.
From birth, this body had faced the threat of death every single day—like a family name slowly decaying toward extinction.
I don't know whether tomorrow or disaster will arrive first.
So he cherished his life. Even during his most embarrassingly edgy phase, he had never once tried to harm himself.
He still didn't know how he had transmigrated. Maybe he'd collapsed while binge-watching anime, face-first into his keyboard.
He had once wanted to study medicine—to cure himself with his own hands. The result he had chased so desperately in the "real world" was now within reach in this one.
And yet, at the moment it became attainable—
He felt nothing but relief.
It didn't matter anymore.
Now, he possessed [Restore].
The instant any abnormality appeared in his body, he could heal himself and avoid death. Ironically, his congenital insensitivity to pain made him immune to the side effects of [Restore]. If he were cured, that might actually be a disadvantage.
Perhaps this was heaven's twisted mercy.
"Humanity still lacks a complete understanding of CIP's root cause," the doctor said with regret. "But there will always be a solution. You understand, don't you? If you can't feel pain, even accidentally cutting your own hand during surgery—"
For a surgeon, that was a catastrophic accident. Infection risk skyrocketed.
"I'll treat my ability with respect," Gen replied, looking down at his hands.
Even [Restore] couldn't fix genetic-level defects. It merely returned things to a prior state. It wasn't as if he could revert himself to a fertilized egg and restart life from scratch.
"I'm glad you can see it that way."
Seeing his student so composed eased the doctor's worries. Perhaps that was why, ever since meeting this intern from overseas, he had grown fond of him and kept him close.
"Shift's over. Let's get dinner."
"Yes, Sensei."
As the frog-faced mentor turned away, Gen adjusted his glasses and murmured inwardly:
Sorry.
If I'm going to survive… I'll be taking the knowledge of the God of Medicine.
What was more interesting was the secret buried in his memories.
Decades ago, "he" had rescued a man hunted by British Puritan magicians in the English countryside—provided him with life support equipment, introduced him to Japan's "spiritual sweet spot," and ultimately helped establish Academy City.
That man was Aleister Crowley.
The doctor could even remotely shut down Aleister's life-support system.
The only regret? He had no knowledge of magic. Even through [Restore], Gen still hadn't touched the magic side of this world.
He knew very well he wasn't one of the three main protagonists of A Certain Magical Index. If he naively believed this intel was enough to negotiate with the final boss, he'd be shredded in seconds—by some silver-haired girl or an angel named Aiwass.
Better to keep it as a hidden trump card.
If the "Upside-Down Man" discovered he had peeked into the frog doctor's brain, he'd be dead.
At present, [Restore]'s copying function had only been exposed within the Misaka Network's calculation framework. Thanks to the camouflage of [Mental Out], occasional memory reading could still be explained away.
Fortune favored the bold.
A transmigrator's ambition wasn't limited to cheating through exams.
The embodiment of all modern and near-future medicine—the one who transcended life and death—
That was the doctor known as "Heaven Canceller."
And now—
I stand at the pinnacle of humanity as a physician.
When the seal on [Memory Manipulation] was lifted, countless skills and memories he had healed and seized flooded back. People from every walk of life—elites and nobodies alike.
The world called it "talent."
For one month, he would not forget.
His brain now encompassed vast swaths of human civilization's knowledge.
He had to act before that window closed.
If [Restore]'s flaw was passive forgetting… what if he copied a memory-enhancement ability?
After all, the so-called "heroine" of A Certain Magical Index possessed perfect memory—
Index.
Gen removed his plain-lens glasses. He didn't need them; they simply made him look older, more trustworthy to patients.
"Yomikawa-sensei, Tetsuzō-sensei—sorry to keep you waiting. Let's go."
After work, Gen left the hospital with the two beautiful Anti-Skill officers and spotted a pink-haired loli politely chatting with someone in the distance.
Komoe Tsukuyomi.
Currently his legal guardian.
One hundred and thirty-five centimeters tall. Sweet-faced. Looked twelve or thirteen. In reality—fully grown.
One of Academy City's Seven Urban Legends:
"The Imaginary Number District has successfully developed immortality technology. The test subject is a high school teacher who appears to be twelve."
The legendary legal loli—acquired.
"So you're a high school teacher, Komoe-sensei. No wonder you've nurtured such an outstanding talent as Doctor Kurokami," the hospital director praised.
Gen's mentor had refused administrative roles to focus solely on medicine. Academy City's Board Chairman, Aleister Crowley, had built this hospital specifically to repay a life debt.
"Oh my, our Gen-chan must have caused you so much trouble." Komoe beamed, her voice syrupy sweet.
"Director." Gen nodded. "Komoe."
"Call me Sensei!"
The pink-haired loli puffed up, jumping to smack his head—though she barely reached his knees.
She hated being called small.
"Of course… Komoe 'Moe' Sensei."
"Hey!"
She covered her face in bashful delight. Praise overpowered irritation every time.
On the drive home, she proudly recounted Gen's recent act of bravery.
Yomikawa snorted. "You're way too excited about reforming one delinquent. What are you, some over-the-top shounen teacher?"
"Yomikawa-sensei, you're just jealous."
"My class is full of honor students," Yomikawa shot back. "And we're off the clock—drop the formal speech."
Gen, having already read their memories, knew the busty Anti-Skill officer's educational passion rivaled Komoe's. The three of them all taught at the same high school.
He thought quietly:
If this hospital's map listing is anonymized to protect Heaven Canceller… then what exactly is that high school hiding?
Komoe drove a compact vehicle modified with accessibility tech. Every evening she picked Gen up from the hospital.
Currently: cohabiting with a legal loli.
"Since Gen-chan, Yomikawa, and Tetsuzō are all here, let's have a fun dinner together!" Komoe chirped. "Though… my car might be a bit cramped…"
"'A bit'?" Tetsuzō muttered as she and Yomikawa squeezed into the backseat, their expressions strained. The real space issue wasn't the cabin—it was their chest burdens.
"No choice. I'll drive."
Gen lifted the pink-haired loli out of the driver's seat and sat down himself. It felt like a child's seat; he had to hunch to avoid hitting the ceiling.
"Gen-chan! Is this how you treat your kind guardian?!" Komoe protested. "Wait—you don't even have a license!"
"I passed one back home… I'm eighteen anyway."
Academy City loosened licensing rules for students, though few needed cars.
"Unlicensed driving and overcapacity?!" Tetsuzō panicked. "As Anti-Skill, we could confiscate this vehicle—"
"Seatbelts."
Gen located the brake and accelerator controls on the dashboard—modified for hand operation.
The engine roared to life.
He sat Komoe on his lap—better than the reverse.
"Driving while holding your teacher… even I'm a girl, you know!" she squeaked, cheeks pink.
Her real age remained a mystery—only that she was older than Yomikawa.
"Unless you'd prefer sitting between Yomikawa-sensei and Tetsuzō-sensei?"
Komoe immediately imagined being smothered between two massive "airbags" and shook her head violently.
Absolutely not!
Among his restored patients was Academy City's top street racer. Even if this model was unfamiliar, muscle memory would suffice.
Through the lens of his inner [Emerald Eye], he reviewed his copied life skills:
The hacker's Guardian Deity.The medical apex—Heaven Canceller.And…
Master Driver.
"Vrrroooom—!"
As the sun dipped below the skyline, a so-called "disabled" mini automatic zipped through traffic like a phantom. Owners of high-displacement engines were left choking on exhaust, staring dumbfounded at the retreating taillights.
"Did that thing just drift?!"
"Is that some Level 5 'Akina Drift King' or what?!"
Though he felt no pain, his sense of touch was keen.
Komoe-sensei's body…
…was surprisingly soft.