The instant I entered this world, I returned to my flesh form. The night air was cool against my skin, carrying the faint scent of woodsmoke and oil lamps.
Unlike the endless wilderness of 10,000 B.C., this place pulsed quietly with civilization.
Lanterns lined the streets, shoji doors slid shut as families retired, and the distant rumble of rickshaw wheels echoed faintly over cobblestone.
This was Taishō-era Japan.
I decided to test one of my core skills.
"Athena," I commanded. "Generate an I.D."
Athena: Random I.D. protocol engaged. Minimum cost: 10 U.P.F. Would you like to designate your background for an additional cost?
"No," I replied without hesitation. "Let's test my luck."
A surge of data flooded into me. My vision blurred—reels of film fast-forwarding through years of false memories compressed into moments. When it finally settled, I exhaled sharply.
So this was me.
Alex Kurogane.
Half-Japanese, half-Indian. Heir of a wealthy merchant family with sprawling estates, shopping streets, and lands under my name.
A boy born into privilege, marked by his foreign blood yet respected for his fortune.
In other words, not a demon slayer. Not a warrior. Not even a name history would remember. Just… a wealthy background character.
"…Hah. Not a bad deal for ten U.P.F."
The implanted memories replayed in fragments—faces, greetings, business deals, idle childhood scenes. I could recall them perfectly at will. Convenient. Exactly what I needed to blend in.
Following those memories, I arrived at my residence: a sprawling villa on the city's edge. Lanterns glowed warmly across wide courtyards as sliding doors opened and servants bowed in greeting. Luxurious, yes—but to me, it felt more like a stage set than a home.
I retired to my new room and leaned against the polished wooden railing of the veranda, gazing into the night sky. Before resting, I checked the calendar tucked inside the drawer.
October, 1908.
For a moment I froze—then a grin spread across my face.
"So… I'm early."
According to my knowledge, Tanjiro's family wouldn't be slaughtered until 1913. That gave me five years before the official story began. More importantly—Kanae Kocho, Shinobu's elder sister, was fated to die in 1910.
Two years from now.
If I could change that fate… the amount of plot force generated would be immense.
But there was another matter I couldn't ignore.
The Blue Spider Lily.
The flower bloomed only between September and November. Which meant—right now. If I delayed even a little longer, I would miss my chance and be forced to wait until the next year's bloom.
I couldn't afford that.
And with my current power and knowledge of the plot, obliterating Muzan would be child's play.
So I made my decision.
I would speedrun this world—while testing a few of my theories along the way.
After making my decision, I sprang into action immediately.
First, I turned to the most obvious advantage I possessed in this identity—wealth.
With my current fortune, it was easy to mobilize informants, merchants, and hired investigators under the guise of business expansion.
Muzan Kibutsuji was many things—powerful, cunning, and above all, a coward. For centuries, he had hidden in plain sight, not as a beast in the shadows but as a respected aristocrat, blending seamlessly into human society.
He played the role of a noble, a doctor, a benefactor—anything that allowed him to cloak his monstrous nature beneath the mask of dignity.
That was his greatest strength.
And also his greatest weakness.
I knew this much from the memories of the plot. Muzan's vanity demanded recognition. He relished the role of a cultured noble, admired, envied, and feared in silence.
Which meant—if rumors of the Blue Spider Lily took root in aristocratic circles, he wouldn't be able to resist.
He wouldn't send a subordinate. He would likely come by himself.
So I tailored the gossip accordingly. Not through peasants or street vendors, but through high-society merchants, influential patrons, and entertainers who circulated in noble houses.
A subtle ripple across Japan's upper class, just enough to reach Muzan's ears without looking staged.
At the same time, the portrait I had commissioned was finished. The artist's brush captured Muzan's pale, aristocratic features perfectly.
With that, I ordered copies—altered slightly with different hairstyles and dress—and had them discreetly circulated through taverns, inns, and backroom markets.
If Muzan changed his form, one of these faces would surface. All I needed was a single confirmation.
The trap was set.
My villa became the stage.
To any observer, I was merely Alex Kurogane—an eccentric young heir with too much wealth and a rumored interest in rare flowers.
But beneath the surface, I was laying bait for the most dangerous predator of this era.
And soon enough, the spider would step into my web.
Of course, spreading rumors wasn't enough. Muzan was too paranoid, too calculating. If he arrived and found nothing, the deception would collapse instantly.
So I decided to manufacture proof.
Before anyone could question the authenticity, I slipped back into my original world—our Earth, the one you know, the one I came from. With my power, it was effortless, a brief detour.
There, I researched every close relative of the elusive Blue Spider Lily. I found one that shared nearly identical traits: the red spider lily (Lycoris radiata). Common, vivid, and historically symbolic—but with the wrong color.
That was easy to fix.