How does fanfic emerge?

James Cameron’s Avatar is still the top grossing movie of all time even fifteen years after its release. It’s followed in the top five by Avengers: Endgame, Avatar: The Way of Water, Titanic, and Star Wars: Episode VII. While Marvel and Star Wars, as properties, have massive transformative fan communities around them, the James Cameron films not so much. These movies certainly have fans. They made a lot of money. People enjoy them. But where is there such a small fan community? Particularly one that creates fanfiction.
This has to do with the nature of why fanfiction is created.
Fanfiction is the weaver of loose end. The filler of gaps. It sees the places where a narrative falls short, grows thin, or doesn’t deliver on expectation and says “what if?” What if this pair of people that the original story didn’t have enough guts or time to properly put together got their own romantic relationship? What happened before the story or after it? What would the opposite perspective be on a major plot element and what could that reveal about the overall story?
When we study the organizational structure of fanfiction, we also find it’s very character-centric. Intricate settings and plots are well and good and a necessary element in the construction of good original fiction. But it’s the characters that people connect with. It’s the relationships and the interactions that inspire in people the desire to create and transform.
So if we combine these elements, we’re able to speculate on the perfect fanfiction-able piece of media. It has to have characters that people connect with and enough space in the story to breed speculation. Only having one or the other doesn’t actually do it. In the case of Avatar, people generally enjoy the main characters. They enjoy the aesthetic and design enough to create cosplays and visit Pandora in themepark form. There’s enough there to compel the sequels. But there’s no space left behind, narratively for someone of the right inclination to find a hole to fill. A gap to cross. The movie doesn’t leave intriguing enough loose ends to spawn a transformative fan community.
Compare that to a larger IP like Marvel or Star Wars. The health of the IP is dependent on leaving space open for new stories for its in-house writers. Those same threads are exploitable by fan writers, as well, and thus a transformative fan community evolves around them. Non continuous or generating IPs (stories that are “done”) still create transformative communities because they are simply “big” in nature and leave far too much behind.
Let’s examine one of the largest fanfiction communities (if not the largest): Harry Potter. Across the seven book series, between students and teachers and supplemental members of the wizarding community, more than seven hundred named characters appear. The main three get the most time, of course, but there’s also a ring of major and minor characters that get just enough information about them to be almost more interesting than the leads. Rowling very briefly opens the door about James Potter’s (Harry’s dad in case you’re unfamiliar) time at Hogwarts as a teen, but there’s very little exploration in text. This created a strong sub community focused on James’s time as a student and who was in a gay polyamorous relationship with who. There’s also a lot of frustration, to this day, with several of the plot choices Rowling made. Dumbledore’s piss poor excuse for leaving Harry with the Dursley’s. Draco’s lack of a good and proper redemption arc. The pattern of the relationship between Lupin and Nymphadora. Then there’s the pervasive “what ifs,” and the series just presents a lot of them. This leads to a thriving transformative community even seventeen years after the last book and thirteen after the last mainline movie. So much so that it self-perpetuates and has developed a complex, intra fandom lingo.
This kind of tells us, as original writers, that if we reach the point where we garner a fan following, what the resulting transformative work might look like. If the story leaves no room for narrative speculation, there won’t be. If all relationships are fulfilling as presented in story, the audience won’t crave more. Leave enough openings, however, and fanfiction writers will worm their way in. How are you, as a creator, planning to interact with this kind of community? How much creative control do you potentially want to share with your potential fanbase? How willing are you to let your baby go?