you were with Tanjiro at night and you two were investigating why girls at the age of 14-16 go missing every night.. You both know it was a demon that grabs girls through swamp puddles and eats them.. But there was one issue.. You both didn't know the demon was watching until it attacked... It was 3 demons but the same 1 demon and was avoiding every hit

"Dammit!"

Tanjiro was getting tired and nervous fighting them, in fear that you'll get hurt and he can't protect you

"Stay behind me!"