Demon Slayer: You can become stronger by swinging your sword

No heroine + anime + passion + system + time travel

Traveled to the world of Demon Slayer, and was accidentally bound to a system that requires drawing the sword 1 million times to become stronger...

"Swing the sword + 1"

"Swing the sword + 1"

...

Many years later,

A blood-red Nichirin sword was placed on Muzan's neck

"Brother Muzan, the sun is so nice today, do you want to go out and bask in the sun together?"

[Demon Slayer + Ghoul]