A Dark Lord in the Making

Harry returns to the Dursleys after his second year but decides to make changes to be treated better. Taking inspiration from his experience with Diary Tom Riddle, he even decides to call himself the Heir of Slytherin to his cousin, hoping to scare him even more.

Of course, it's only a matter of time before Harry is caught casually using the title Heir of Slytherin... by non-other than Marvolo Gaunt. (aka Tom Marvolo Riddle)