A Nine-Dragon Coffin from the Start, and I Turned Muzan into a Demon King

[Invincible + Mastermind + Wish-Fulfillment + Ruthless + No Goody-Two-Shoes]

After transmigrating into Demon Slayer, Lin Yuan, a Tsinghua-trained biology PhD, had hoped to use science to cure a frail young man.

Who could have guessed that the “Nine Dragons Coffin” workout regimen would be so effective that it turned the patient into the Demon King himself: Muzan Kibutsuji!

Having made a terrible mistake, Lin Yuan took an even stronger drug himself, both to correct the error and to protect himself!

From then on, the world had one fewer doctor healing the sick and one more... perfect Demon King, walking beneath the sunlight, wielding “science” as a weapon and hunting the “creation” he had made...

“Come along, Muzan. Your god, here to teach you one final biology lesson. Signed, your ‘Creation Number One.’”