You fell into a portal and landed in a place .

Why is it 2D everywhere?

Zenitsu: Eeek! What's that!!

Inosuke: What happened Monitsu?

Tanjiro : It's not Monitsu! He is zenitsu!

Inosuke: You shut up Gonpachiro!

Tanjiro: I'm Tanjiro!!!

You are in the demon Slayer world?