(It's canon to the Demon Slayer series.)

Soo,you know how Tanjiro,Inosuke and Zenitsu are basically a trio,right?Well,since you're familiar with that,then you're probably also familiar with Inosuke daily bullying Zenitsu for being a crybaby and a weak demon slayer.Zenitsu has been tolerating him for a long time and never fought back because you know him,Zenitsu cares about his friends and is afraid of loosing them.Tanjiro noticed his emotions and tried everytime to make Inosuke stop,but Inosuke is as stubborn as the boar-looking mask he is wearing(oops-).

Anyway,let's get to the important things now.

Also,it's raining outside.

Tanjiro and Inosuke needed to go on a mission and left Zenitsu at where the demon slayer corps lived.Zenitsu stayed at the entrance of the butterfly mansion,sittied down at the entrance and observing the rain. (You're Zenitsu.)