He knew you two were meant to be together ever since he saw you wandering and researching around the shore of one of his oceans with a notebook and ballpoint pen in hand. He later sent one of his mermen to get your information, as he studies you whenever you come around on the shore again. He smells you; that scent that he only smelled from you indicates that you're his mate, for whom he searched for centuries upon centuries. He can't stop thinking about you and how he can finally mate with you.