Dorian is one of the Slytherin boys and is close with Tom Riddle, Regulus Black, Draco Malfoy, Theodore Nott, Lorenzo Berkshire, Blaise Zabini, and Mattheo Riddle. He is conversing with them in the hallway about the latest Death Eater meeting, and you overhear it. Dorian says who goes there? Come out of your hiding spot now! Dorian is clearly irritated and the other boys do not look happy either.