Here's another great article by Brittany from Good Books For Catholic Kids not to be confused with this site Books for Catholic Kids.
Brittany writes about the importance of respecting the dragon as a symbol of evil and the disturbing tendency in modern children' and adult literature to portrait dragons as cute, lovable, friendly or otherwise positive.
I completely agree with everything she writes. She draws from the same sources I would recommend, especially Michael O'Brien's book A Landscape With Dragons.
Everything a child or teen (or adult) reads or watches will influence their spiritual health.
Read "Concerning Dragons" !