Crossover Anime: Starting with Bankai from Demon Slayer

Let's rewind to three months ago.

Tokyo, formerly known as Edo, is now the heart of the country and its political center.

Inside a luxurious mansion in the city, exuding Western charm, a formidable shadow is lurking.

Outside the huge floor-to-ceiling windows, the garden plants are meticulously trimmed, forming an elegant landscape with several Western-style sculptures.

Inside, expensive Persian carpets were laid out on the floor, and luxurious yet cold ornaments and paintings were everywhere, revealing the extent of the homeowner's wealth.

This is the residence of Hirota Taizo, the research and development manager of Suzuki Pharmaceutical.

His main project is the development of plasma preparations for emergency treatment on the battlefield or for deeper exploration.

Right now, he is pointing out the pharmacological effects of different plants to his adopted son, Junguo, by referring to a book.

Suddenly, Jun-guk, dressed in an elegant white shirt and appearing extremely well-mannered, twitched his brow and stretched lazily, yawning.

"Haha, Jun-guk, are you sleepy? Well, you've been studying until the wee hours. You're such a diligent kid." Hirota chuckled, patted Jun-guk's head, and closed the book. "Get some rest. We'll continue tomorrow."

To Hirota Taizo, Shunkuni was the perfect adopted son.

He is knowledgeable, reasonable, kind, and exceptionally ambitious.

The only pity is that he has a skin disease and can't be exposed to sunlight. He can only study at home by himself and has no friends to play with.

Thinking of this, Hirota's gaze became somewhat profound:

"I need to urge those experimental projects to hurry up and produce the effective drug! I can't let my Junguo never see the sun again!" he thought.

After he left, Jun-guk gracefully got up from the bedside, tidied his smooth black short hair, and stood in front of the French windows.

In an instant, his pale purple eyes suddenly turned, revealing his scarlet pupils!

A figure appeared in front of him in a disheveled state, kneeling heavily on one knee on the thick carpet, with one hand still covering his neck.

Upper Moon Three - Akaza.

His strong body still bore the marks of a fierce battle, especially the gruesome wound on his neck.

Even with the speed of the upper arc's recovery, two days have passed and the fatal wound torn open by the burning Nichirin Blade of the bird has not yet fully healed.

The edges of the wound were unnaturally charred, and you could see granulation tissue formed from dark red ghost blood trying to stitch it up, but it was resisted by a faint, reddish-black fighting spirit, making the progress extremely slow.

Akaza did consider tearing this piece of flesh off directly, enduring the pain for a while, and then letting it grow back.

But his fighting instincts fueled a fierce determination to overcome the suppression, and he wanted to use his own regenerative abilities to survive until now.

At the same time, this is also a humiliating mark he has branded himself—he was defeated by others, and he must get his revenge!

"Akazata." Jun-guk's childlike, clear voice was devoid of warmth, icy and piercing, like a scalpel scraping against glass: "Report."

"Yes, Lord Muzan..."

Indeed, the person before us is none other than the Demon King, Muzan Kibutsuji.

He changed his body once again, infiltrating the pharmaceutical company's home as an adopted human son, all to use these scientists to help him find a way to overcome the effects of sunlight.

Muzan himself was extremely cowardly and selfish, unwilling to even part with a single blood sample, fearing that someone would discover his weakness.

Once the owner has exhausted his usefulness to him, he will not hesitate to completely eliminate him and disappear from public view....

Akaza, not daring to look up, began his report in a low voice: "...The Mugen Train mission failed. The Lower Moon Enmu was slain, but the targets, Kamado Tanjiro and the demon girl Nezuko, were not captured..."

"The reason for the failure? Don't make me rack my brains, Akaza," Muzan said coldly.

"...I encountered the Flame Pillar of the Demon Slayer Corps and...a Pillar-level swordsman who calls himself Storm......they are very strong..."

"Strong? They're just two Pillar-level beings, what's so strong about that?"

Muzan is really getting angry; in his view, it's only natural that demons are stronger than humans.

Let alone two pillars, even if all nine pillars gathered together, they would still be nothing more than a bunch of good-for-nothings.

This wasn't the first time he'd made the Demon Slayer Corps flee in terror, so naturally he was very dissatisfied with Akaza's performance.

"Tell me, Akaza...aren't you being too lax?"

"You always talk about pursuing the pinnacle of martial arts, but haven't you tasted fresh, vibrant flesh and blood in far too long?"

"Have you gotten weaker? Has your strength declined?"

Just as Muzan was about to unleash his fury again, he suddenly frowned and noticed Akaza's unnatural gesture of clutching his neck.

He twitched his fingers slightly, and Akaza involuntarily released his grip, drawing Akaza's attention to the not-yet-fully-healed wound:

"This kind of injury again..." His gaze swept over the eerie feeling of Akaza's wound, and he reached out a finger to touch it.

It's so hot... His heart skipped a beat, and he remembered some unpleasant memories.

"Lord Muzan...I..." Akaza was about to explain the unusual wound when he heard Muzan's stern voice:

"Shut up!"

His small figure exuded a terrifying aura, and his childlike, slender hands suddenly grabbed at the unhealed wound!

Sizzle—!

A tearing sound rang out, and Muzan's fingers, like five sharp steel hooks, mercilessly pierced Akaza's body, grabbing the flesh and blood tissue that was hindering his self-healing and pulling it outwards fiercely!

".....Uh." Akaza groaned, his fist clenching tightly against the ground.

Under Muzan's destructive will, one not only has to endure the pain of flesh being torn apart, but also the terror originating from the very source of one's bloodline.

But he dared not utter a second cry of pain, only breathing heavily.

In the blink of an eye, a bloody hole was torn open in his neck, deep enough to expose the bone, but it quickly began to heal.

Muzan's small hand gripped the charred, bloody flesh that had been hindering Akaza's self-healing, and her pupils contracted slightly.

Beneath the fractured texture and charred surface, he could sense a faint yet persistent, strange fluctuation...

"This is..." He remembered the uncomfortable feeling in his stomach when he swallowed Lower Moon Two, Rokuro, and the fluctuations emanating from it were exactly the same...

He stopped looking at Akaza and went directly to a corner of the room, to an ebony cabinet with brass clasps.

Opening the cabinet door reveals a variety of exquisite glasswares and chemical instruments neatly arranged inside, resembling a miniature laboratory.

He quickly took out a specially made glass flask, carefully placed the charred flesh that still retained its eerie power into it, and sealed it with a specially made cork.

Muzan stared at the flask, a cold and dangerous light flashing deep within his scarlet eyes.

He felt he had discovered some extremely dangerous, yet highly valuable, unknown force...

He locked the cabinet door again, and when he turned to face Akaza again, the brief surprise on his face had disappeared, replaced by that chilling coldness.

Without Akaza needing to say another word, he directly inserted his cold, tiny fingers into Akaza's forehead.

"Let me see what kind of thing that swordsman who made you look so pathetic really is." Muzan's voice was completely calm.

Akaza was unable to resist or refuse.

Muzan's will brutally invaded the depths of his mind, rummaging through all the fragments of his memories of the battle on the Mugen Train:

Kyojuro Rengoku...Breath of Flame...A boy with an earring...

Muzan scrolled through these images one by one, finally fixing his gaze on the black-haired boy.

His Nichirin Blade became as hot and red as molten lava, its blade even humming and trembling from the force it bore...

At the corner of his eye, the hideous red and black jagged markings... were like living flames, constantly stinging Muzan's gaze...

boom--!

An overwhelming fear, originating from the deepest part of his soul and spanning hundreds of years, erupted in Muzan Kibutsuji's heart like the most violent volcano!

This scene instantly overlapped with his deepest and most profound nightmare, which he could never escape for the rest of his life!

The man who terrified him so much that he was forced to split into 1,800 pieces to escape!

That nightmare that utterly shattered his lofty altar of perfect being, leaving him to hide like a stray dog ​​for hundreds of years!

The mere thought of that name could freeze his blood and instinctively make him want to flee at all costs—

Yoriichi Tsugikuni!