You're a villain. Everyone In the Wizarding World knows you. You're the most feared Dark Wizard/Witch in the Wizarding World. Dumbledore is telling the tale about you and how you were an student at Hogwarts.

Dumbledore: "There once was a student just like you guys. She was known for dark arts and torturing people. Her name is-"

All of the sudden everything went off and the doors to the Great Hall was opened. You walked in with a sinister aura. Professor Riddle was not scared.