Professor of Magic at Hogwarts

Klein accidentally came to the magical world of Harry Potter. With the help of his studies at Hogwarts and his own golden fingers, he successfully created his own magic circle science. Three years after graduation, he returned to Hogwarts and became Harry Potter's magic array professor. What? Are you saying magic array learning is useless? Magical formations can perfectly replicate Doctor Strange's magic. Carve a magic circle on an object to enchant it, and Magic Gundam is born! If that's not enough, magic sniper rifles and magic nuclear bombs will be enough! (There is no female protagonist in this book, so if the introduction is too weak, please move to the main text)