ONE

Taehyung's a swan, who can secretly turn into a human.

but he's no regular swan, no, he's a blue Swan and there's a couple he's taken home with that are unsuspecting of what their actually bringing into their home.

Or

Taehyung's a rare swan breed who has never seen the human world and shifts into his human form so he can be closer to 'his humans' who knew nothing about this. All romance and hell ensues.