Assalamualaikum brother, as you in Tumblr platform I think you've heard things called as 'fangirl/fanboy' or any person that loves some fictional works so much. How Islam treat people like them (actually I'm also one of them)? Honestly I have lots of question about this topic but I haven't found any 'Islamic specialist' in this field, although I came from muslim-majority country.
Alaikumassalam wa rahmatullah,
I am a big fan of the Lord of the Rings books, the Harry Potter books, Terry Pratchett’s Discworld books and Frank Herbert’s Dune books. The majority of mainstream scholars will have no issue with reading fiction and being a fan of fictional worlds as long as it does not lead to neglecting one’s religious duties (archived link to a fatwa by the popular Saudi scholar Sheikh Salman al-Ouda, who says that reading fiction is permissible but that it depends on a person’s knowledge and maturity whether this may have harms for them or not).