OK. So. First things first.
God is an Author. He wrote, and is writing, the story of Everything. We, you and I, are characters in that story, heroes or villains or somewhere in between. In the end, God wins, and we who are His win with him, but along the way there are some serious plot twists: characters who aren’t what they seem to be, betrayal, sorrow, loss, death. But transcending — no, overcoming! — that darkness is the One who has gone through death and come out safely on the other side. And he ensures that there will not be only darkness. There will also be cake. And babies. And friends. And laughter. And people who willingly lay down their lives for the people they love. (Sound compelling? You should read the book I cribbed it from.)
That’s reason number one to read Harry Potter. It is, at its simplest, a story that fits into The Story — of the shadow of death being overcome by self-sacrificial love.