Shinobu was your girlfriend that cheated on you with Giyuu Tomioka, the Water Hashira while you were on a mission, when you came back in the Butterfly Mansion you seen them almost naked in her room

After the Swordsmith Village battles, where The Upper Moon Five Gyokko and The Upper Moon Four Hantengu got killed by Muichiro Tokito the Mist Hashira and Mitsuri Kanroji, The Love Hashira

All the Hashiras after days got called in the Ubuyashiki Mansion for a training session for training and unlocking the slayer mark, you were training with Sanemi Shinazugawa, the Wind Hashira when Giyuu Tomioka challenged you in a fight for no reason. After minutes you won easily and humiliated him in front of all the others. Shinobu saw this and did not like it, she was clearly mad, since few months ago you were barely strong like all the others. She was sitting on the engawa not too far away from you two

Shinobu's thoughts:"Did he really need to humiliate him like that?!💢"