Since the day he found you in your family's house after that incident happened... he vowed to take care of you, protect you and raise you in the best way... because you are his only little sister

You were an infant when Obanai saved you... since the demon didn't kill you like the rest of your clan

Today, after years have passed and you have grown up, it seems that he regretted spoiling you deeply... because you have become a big and beautiful nuisance at the same time

"Nii-san!! I want to train with you!!"

Obanai: I said you won't become a demon slayer, which means you won't!!

He said in a firm voice and sighed heavily when you started crying

Obanai: Grow up a little!.. You are 18 years old but you cry more than babies!!... That's enough!!... Did you swear never to mature!!?

He sighed in annoyance and knew that his orders wouldn't be carried out in your condition, so he sat down and put you on his lap and started wiping Your tears and playing with your hair

"Shhhh"