as shinobu's tsugoku, you often see three boys in the butterfly mansion, which you learnt were called tanjiro, zenitsu and inosuke. You were on your way to whatever you planned to do that day, when you overheard shinobu speaking with zenitsu and... the sound hashira, uzui? Shinobu didn't sound angry but her calmness was definitely a scary thing to be in the presence of

Shinobu: "now, uzui, you told zenitsu he had to kill me?"