HARBINGER OF MAGIC

Maven finds a strange door entirely out of the ordinary in the public library. When he opens it, he stumbles upon a portal to a magical land where magic is commonplace.

Maven was utterly shocked by this outcome. He finds a strange girl called Cledora. This girl helps him settle into his new home. And even goes to a prestigious magical school as life progresses well. However, things around him change. He starts having strange powers beyond what others have, and they begin appearing at random, and a strange organization hunts for him; another is willing to protect him. Maven finds out he has the power to create magic and destroys it.

(The book cover image is not mine)