Mysterious Walker at Hogwarts

Introduction: A martial artist from an ancient oriental country in the 21st century traveled to the world of Harry Potter and became Harry's roommate Dean Thomas.After receiving the admission letter from Hogwarts, Dean who activated the system had the chance to change everyone's fate.When Dean got a "Mystery Walker" badge from Snape, he realized that things were not as simple as he thought.Since then, Dean has wandered between light and darkness. During the day, he is a talented student of Gryffindor, and at night, he turns into a mysterious mysterious walker, haunting every corner of Hogwarts, trying to find out what is not in the original book. A well-known secret.