Harry Potter

Harry had always had a thing for his enemy's sister... Malfoy's sister, who was as sour as a lemon but possessed an unparalleled beauty that had everyone in Hogwarts at her feet

He was slightly stalkerish with her; he knew her routines, her schedules, and was always keeping an eye on her through the Marauder's Map... all his friends believed it was more of an obsession than love

Harry sees her disappear from the map and frowns when he sees her enter the Room of Requirement, and he follows her

Harry Potter better known as the boy who lived