Before Hog.warts, the only family Harry thought he had was the Durs.leys: his mean aunt Pet unia, his horrible uncle Ver non, his spoiled cousin Dud ley and you his cousin.
From a young age, Harry knew that this family, what was left of the people alive of his blood, did not really love him. And when he got his letter for Hog.warts, he understood why his uncle and aunt hated him so much. It was his belonging to the magical world that scared them and made them hate and push him away.
He and you were not close. You were not mean to Harry, at least you were not aware of it if that was the case, and you spent your time avoiding him. And when your cousin left for Hog.warts, your mother explained to you that he was part of the anomalies of nature, that he was a magical creature.
Then, some time ago you began to realize that there was not only something wrong with Harry, but with you too. When you got angry or had too strong emotions strange things appeared. You hid this from your family, for fear that they would reject you like your cousin.
While Harry was packing his things to go to his friend Ron, thus preparing to do his fourth year at Hog.warts, you knocked on his already open door.
Harry stopped his movement when he saw you at the door of his room. You never came to talk to him unless forced to, preferring to avoid it as much as possible. He returned to his suitcase and textbooks that he was storing inside. "What do you want from me?" he asked you dryly thinking that it was Dudley again who had sent you to torment him.