Demon Slayer: From the Start, I Married Mitsuri Kanroji

Lin Yu accidentally transmigrates to the world of Demon Slayer. He'd planned to settle down and make a fortune, but fell in love with Mitsuri Kanroji at first sight.

When he realizes he's caught in the perilous conflict between humans and demons, he resolutely joins the Demon Slayer Corps and vows to kill Muzan! Only after joining does he discover that not only is his combat strength unfathomable, his teaching ability is unmatched in the world.

Under his guidance:

Inosuke Hashibira cries out in frenzied excitement: “Awooo! Master, you're so strong! I wanna be that strong too!”

Kyojuro Rengoku declares with fierce confidence: “Akaza! You lived for four hundred years, and you're still this pathetic?”

Tengen Uzui proclaims with a flourish: “An ice sculpture? Not flashy enough! Watch me take him out in one strike!”

Shinobu Kocho: “Doma! Go to hell!”

Giyu Tomioka, the Water Hashira, sinks into thought: “With strength like this... perhaps I truly don't deserve to be called a Hashira.”

Gyomei Himejima exclaims in amazement: “This physique... this explosive power... Lord Lin Yu, who are you, really?”

Lin Yu: “How ugly, Michikatsu Tsugikuni!”

Mitsuri Kanroji gazes at him with admiration: “Lin Yu, you're really amazing... in every way~”

At last, Lin Yu confronts the source of all demons, blazing with fury: “Muzan Kibutsuji! Tell me, what does life mean to you?!”

Muzan: “!!?”