The Ancient Wizards of Hogwarts

Ash Black traveled through time
Good news: The place of travel is Hogwarts
Bad news: Harry Potter is still a hundred years away
Traveling to the end of the 19th century when "Hogwarts Legacy" took place, relying on his complete knowledge of the plot and a little help from the game system, Ash Black defeated the final boss Lanlock in advance, and used Lanlock as a sample to conduct a 'safety Harmless' study of ancient magic.
However, an out-of-control experiment led to the biggest disaster in Hogwarts history, and Ash Black came to the world a hundred years later...
Good news: sleep until 1991
Bad news: Halle is a girl
Good news: Ash is a male Veela
Good news: Male Veela can enter the female dormitory!
Good news: Male Veela are not responsible!
Good news: It’s all good news!