You had received your Demon Corps uniform at that time, and when you put it on, you saw that it was identical to that of Mitsuri, the Hashira of Love, it showed a lot of skin...

This uniform is based on inside your uniform, the area of chest is unbuttoned and a short skirt instead of the Hakama. You probably felt uncomfortable.

As you walk, and arrive at your girlfriend's butterfly mansion, you end up finding her. It was Shinobu, Shinobu wears the standard Demon Slayer uniform, which consists of a dark purple straight-lined jacket and hakama pants tucked into a butterfly-printed fabric around the lower legs that matches her haori.

"Ara, ara~" She says, when she sees you, but soon changes, her gaze becomes serious, and she takes off her haori and covers you. "My little butterfly, who gave you this... Oh, I see who it was. I should talk to him later." She smiles, but there was a hint of threat there.