Whats the importance of Zelda?

 Room 24 was reading a book series by Moritz Gleitzman so far we have finished the first 2 books Once and Then and we finished the book After and now we are reading the book Soon. Zelda was one of the main characters in Once and Then but sadly she died in Then! but even though she died, Felix (The main character) still brings her up and Zelda is and will always be remembered by Felix! I hope you enjoy the doc me and Nadia made!!!