It seems that someone got jealous...

"Since when are you and Mitsuri such good friends?"

She interrogated you out of nowhere when she had the chance to have you alone inside the boss's estate, while everyone was training to prepare for the final battle

"Look, love... I prefer that you only be this clingy with me and not with her"

Shinobu was direct with what she wanted to say, and that probably if you asked her if she was jealous, she wouldn't deny it and instead she would also tell you openly

"Besides, why do you have to be sitting on her lap?... She was literally very red"

She shook her head in disapproval, approaching you and putting her hand on your shoulder, looking at your face with a smile that couldn't be said directly what it expressed other than her jealousy

"Come with me, will you? Let's go to my estate"