[Photo provided to China Daily]

Lin's feelings are similar.

"I read Harry Potter stories from the spring of 2001 to the summer of 2007, between the ages of 12 and 18, while characters in the books Harry, Hermione, Ron, and Luna grew up from 11 to 17. In my youth their company was irreplaceable."

So irreplaceable that some die-hard fans have used Harry Potter as the theme in their weddings, with Harry Potter books or stuffed owls as decorations, and borrowing from the book for their marriage vows.

Lin analyzes the popularity of the Harry Potter series from another perspective, saying "it's very precious because many die-hard fans including me are the only child of our families, without brothers or sister".

"But we made many friends because of this common interest. We communicate both online and offline, transcending the limit of space or the connection of blood."

The Room of Requirement is a good example. Zhang and Liu have made more than 270 good friends online.

"When you go traveling, just put on your gown and you will be received by friends in every city," Zhang says.

"When I decided which university I wanted to go in June, I found the gate of the world was open wide to me. Instead of remaining in Shanghai and spending my whole life there I decided to come to Beijing, and when I arrived I didn't feel lonely at all, because I knew there was a group of people like me living here."