Finding a town was easier than expected.
Smoke rising through the trees led me to it—a small settlement nestled between forest and fields, wooden buildings clustered together like frightened animals seeking warmth. The moment I stepped inside, I felt it: life, fear, exhaustion. Ordinary people trying to survive in an extraordinary hell.
I didn't ask questions.
I didn't need to.
As I passed through the streets, my gaze met theirs—briefly, casually—and I reached out with Legilimency, soft and precise. I skimmed memories without leaving a trace. Names. Faces. Fear of demons in the night. Rumors of swordsmen who breathed fire and water.
Dates.
Era.
My steps slowed.
"…Sengoku," I murmured under my breath.
The realization settled heavily in my chest.
The Sengoku Era.
Five hundred years before the main story.
I exhaled slowly, relief and dread intertwining. I knew this much, at least. I hadn't memorized every detail of Demon Slayer—not even close. I'd watched the first two seasons, seen countless edits, absorbed fragments through fan theories and discussions.
But I knew this era.
Yoriichi Tsugikuni.
The greatest swordsman to ever exist in this world.
The man who nearly ended Muzan Kibutsuji outright.
That alone anchored the timeline.
If my knowledge was even roughly accurate, then I was standing centuries before Tanjiro Kamado would ever draw breath.
Five hundred years.
Too early.
My mind immediately turned cold and analytical.
Even with magic reinforcing my body, even with potions, rituals, and enhancement spells, my natural lifespan would cap out at around three hundred years at best—assuming perfection. Beyond that, decay would set in. I'd become slower. Frailer. A relic clinging to relevance.
An old man watching history pass him by.
And that was unacceptable.
Because Muzan Kibutsuji would still be alive.
And I had to kill him.
The system panel flickered faintly in my peripheral vision, as if reacting to my thoughts.
[MAIN QUEST: ELIMINATE MUZAN KIBUTSUJI]
I frowned.
The reward was unknown—deliberately vague—but that only made it more tempting. Muzan was the central pillar of this world's suffering. The progenitor. The apex predator.
There was no universe where killing him resulted in a trivial prize.
But therein lay the problem.
Muzan was the power ceiling of this world.
Even Yoriichi, with his absurd talent and Sun Breathing, had failed to finish him. And while I possessed magic alien to this world, raw power alone wouldn't be enough—especially not centuries from now, when my body would betray me.
I needed time.
I needed youth.
And I needed something more than human.
My gaze hardened.
Demons.
Specifically—
Demon blood.
The thought didn't disgust me. It intrigued me.
Demon biology in this world was extraordinary: regeneration bordering on immortality, ageless bodies, immense physical power. The drawbacks were obvious—sunlight, Muzan's control, madness—but drawbacks existed to be solved.
And I had an advantage no demon had ever possessed.
Magic.
Tom Riddle had been a prodigy at alchemy. Potions. Biological alteration through ritual and controlled mutation. I understood blood magic on a fundamental level. Souls, vessels, anchors—I had studied them all.
If Muzan could achieve pseudo-immortality through a cursed medicine…
Then I could do better.
I wouldn't blindly inject demon blood and hope for survival like some desperate fool.
No.
I would analyze it.
Dissect it.
Refine it.
Remove its chains.
As I walked through the town, already withdrawing my presence from the minds I'd touched, a plan began to take shape—slow, intricate, inevitable.
I would study demons from the inside out.
I would master their curse.
And when the day finally came—whether in fifty years or five hundred—
Muzan Kibutsuji would face something far worse than a swordsman.
He would face a wizard who had outlived history itself.