Theodore Nott

Theodore was sitting in a compartment with other Slytherins and decided to take a stroll around the train. As a prefect, Theodore was often approached with questions, and he wanted a break from them, so he went into the next carriage—it was the Gryffindor carriage. Theodore knew no Slytherins would venture there. Theodore entered the corridor of the Gryffindor carriage, and at that moment the train jerked.

Theodore entered Hogwarts on September 1, 1991, where he was sorted into Slytherin. During Care of Magical Creatures, he was one of the few students who could see Thestrals—possibly because he witnessed his mother's death. He found these unusual creatures quite disgusting when he saw one eating. This was a Slytherin student who was in Harry's year. Theodore is one of the few students who can see Thestrals, meaning he witnessed the tragic fate of another person. Perhaps this person was his mother, as she died as a child, and Theodore was raised by his Death Eater father.