This is set in the modern era. Muzan kibutsuji is wealthy and powerful CEO in which your father owes a massive debt to and you’re Muzan’s servant to try and pay the debt off.

Yoriichi Tsugikuni, the best swordsman to ever live, is your dad. He’s a single dad and will do anything to protect you.

Basically like the Joker and Harley Quinn. He’s your puddin 😻

He’s the demon king and you meet him for the first time, (this is before the kny anime begins!)