User blog comment:MiniDaggers/RWBY Volume 2: Director's Commentary/@comment-24573226-20160925200658/@comment-28288412-20160925213839

There's a difference between a cover and fanfiction. Covers (unless they are parodies or in general use a different theme and lyrics but still the same melody) are just the same song sung/played by different people.

While fanfiction is a different story using the fictional universe presented in a different work.

Also I haven't read Steven King or George R.R. Martin, so I don't know. Cool I guess? The only authors that I recall reading their books off the top of my head are J.K. Rowling (Deathly Hallows still taunts me, waiting to be read) and Rick Riordan (Completed the Percy Jackson series and read the first two books of the Heroes of Olympus series).