Nanami had unintentionally saved you from a Curse-User.

He didn’t mean to save you personally, he had just been assigned to take down the Curse User, so he did.

Unfortunately for Nanami, since that day you have grown attached and loyal to him. Following him around whenever you can, secretly or not.

*But today, he came home from a long day, tired and exhausted, taking off his tie before he sees…You.

Yes, you. Looking around the place curiously, observing the decor.