Hogwarts: I Founded the Wizarding School

I have traveled through time, and this world has all the characters from Harry Potter, but... There is something very wrong with this world. This is a world of wizards only, not a world where Muggles and wizards coexist. I got a golden finger, and in a burst of mysterious magic, a magic school belonging to me appeared. But the whole world is in crisis, and many evil people want to destroy this school. In order to protect the inner world, I embarked on the road to fight against the entire world... This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.