I got isekai'd.
The method had a certain... brutal effiency.
Takakai was on his way home with instant noodles, ham, and eggs—ready to treat himself—when a blaring horn startled him. He turned to see a runaway truck barreling toward him, its grill screaming "Isekai tensei no jikan da Shounen!" before sending him flying. Then, for good measure, it ran over his skull for a clean isekai transition.
Imagine a watermelon smashed by a baseball bat—splattered everywhere. Not that Takakai could confirm firsthand, but the last thing he saw was a tire filling his vision, followed by screams and camera flashes.
Anyway, let's not dwell. This isn't #gore—no need for 18+ details.
Long story short: after rebirth, he found himself replacing some Japanese immigrant family. Despite neighbors having ultra-Japanese names, his health insurance card still read "Takakai"—same as his past life.
He suspected it was a body-transmigration, not soul, since his height, moles, and even his clothes were identical—right down to the tire marks and suspicious red-and-white stains.
...Wait, those dried stains—were those his brains?
Post-isekai, he inherited a two-story house with yard. The sole bank card had an 8-digit balance, with the PIN helpfully taped to it. The account name? "Takakai"—same as his.
After digging through records, he theorized this was a parallel world. The original Takakai here was nearly identical—just skinnier—and, like him, an orphaned Cat Guest™ protagonist with zero social ties.
He even found the guy's diary (mostly mundane ramblings), painting a picture of a NEET dropout living off savings, gaming and anime-binging in isolation.
"Who even keeps a diary? Cringe."
After thorough inspection, Takakai sighed, holding the diary.
Well, guess I'm stuck here. Sorry for stealing your life, but since there's no going back... I'll live it for you.
Honestly, the setup was too perfect—no family, no connections, loaded with cash and property. Almost like... it was arranged this way.
Am I some protagonist destined for greatness?
As a failed web novelist in his past life, Takakai couldn't help but fantasize.
"Alright, standard isekai protocol: where's my cheat? Cat Guest MCs usually get Systems, preferably a check-in-for-OP-powers one, since their Systems tend to be useless anyway. So... System? Hey, System? System-chan? System-sama? ...Huh. Nothing."
After embarrassing himself with increasingly desperate calls, he gave up.
"Guess it's a no-System slice-of-life start. Fine by me—less murder, more chill."
He booted up the gaming PC (courtesy of OG Takakai) to research this world.
Oddly, despite everything being in Japanese (or English, French, even Arabic), he could read and speak it all fluently.
Wait, is my cheat multilingualism? ...Kinda lame.
After some digging, he confirmed: this world was basically normal. No man-eating monsters in news, no gas-exploding Fuyuki City, no Umbrella Corp or Miskatonic University, sun not dying, no alien arrivals.
Seems like a normal, peaceful world.
Then he stumbled upon Shuchi'in Academy.
Shuchi'in?! As in Kaguya-sama: Love is War*?!*
A quick search confirmed the Shinomiya Group—yep, Akasaka's universe. Further digging revealed no Soubu High (sorry, Yukinoshita), no Toyogasaki Academy (no Kasumigaoka Utaha), but Suimei University existed (Sakurasou crossover possible?) and "Guitar Hero" was trending online (Bocchi confirmed!).
Conclusion: A slice-of-life harem crossover world!
Behind the house stood a mundane storage shed. Inside, among gardening tools: a pristine black box with a note:
[Do not let anyone know where you came from]
As Takakai touched it—
Darkness.
A voice, genderless and dripping with malice, whispered:
[Welcome to the "Sacrifice Game"]
[Your stage: Twilight]
[May you witness the end in true terror.]