Kimetsu Between the Scenes!

Kimetsu Between the Scenes! (きめつのあいま!) is a spin-off series from the Kimetsu no Yaiba (Manga) written by Ryoji Hirano.

Description
The series is a colored, chibi version of the original series, which follows a yonkoma structure. The series was released during the original run of the anime and thus only covers the Final Selection Arc through the end of Rehabilitation Training Arc.