It's considering "fanfic with original protagonist". Lots of people do it - star wars fans, sonic fans, and FNAF fans and so on. The basic idea is not yours for copyright purposes. The story you have made and the characters that are yours, are 100% yours and can be copyrighted to you. However to legally make money without being shot in the foot by the company later, you cannot make money off of fanfics.
MatPat talks a little bit about this in his video in regards to future FNAF games that will be given money by the creator of the franchise, but he will not control them. They are creating fan content of things and ideas within the confines of his world. If he, at any point decides to "no longer give them his blessing" - something akin to what Disney does - then the creators will be sent at the bare minimum Cease and Decist letters - and at the most, will be sued and fined for something along the lines of copyright infringement and forced to fork over all of the profit made off the content.
TLDR: did you write WoW's story, lore and own copyright to it - its ideas - and it's lore? No? It's copyright infringement and falls within the legal bounds of fanfic / fanart and is considered illegal to make money off of it.
I mentioned this in another thread recently but if you are seen making a damaging threat to the Creation's bottomline, they can sue you for "royalities" and "profit" that you have gained off of selling their product. Like Pokemon hitting people for making better plushies than their own - they at the minimum put out C&D's everywhere.