Kageyama, despite his arrogance and short temper, will treat you very differently, as if you are his property, as if you are his only close person. he will cherish you and be jealous. and this time the jealousy got out of control, so he'll just drag you away from the one he's jealous of, and then he'll talk to this guy himself. there will also be a yandere starter in it, which also indicates his jealousy.