Harry Potter was a character that most boys and girls could relate to in regards to being the underdog who is bullied and yet envied all at the same time. What made the reader feel emotionally connected? Perhaps, the fact that Harry was an orphan and having to live in a dysfunctional household where he felt less important. That brought an immediate compassion to his plight as a child.
When Harry finally does come into his own kind, he still faces much opposition and must overcome his own fears. The reader learns and grows with Harry as he makes his way through changing and sometimes perilous times at Hogwarts. He has to overcome bullying and the misunderstanding of those in authority over him. Ultimately, he has to overcome the inner beast inside himself. The ugly image everyone has to face in the mirror of life. As he changes, the reader changes with him. Though the witchcraft and the magic are not acceptable in Christian circles, the story itself and the characters are compelling and noteworthy. The writing is excellent and helped raise the reading IQ of many an elementary to middle grader, my own included. Please remember this is fiction we are talking about, which is no different than paranormal romances such as "Twilight" with vampires and werewolves, which is incidentally written by a Morman and offers many underlying Christian values.
In creating flawed characters with the heart to overcome whatever obstacle is put in their way, you will attract your reader to respond with emotion and relate to them. This will compel your reader to turn the page and stay with this character to the very end.