Writing Fanfic: Headcanon

Here’s a slippery little beastie; neither official canon nor a fandom semi-consensus of fanon. Headcanon is a writer’s own personal explanation for events, character tics, and various bits of worldbuilding that canon either leaves gaps in or doesn’t explain to a writing fan’s satisfaction. So you make up something that seems plausible for the world and isn’t contradicted by canon, and go from there.

For example, take the character of Ikoma, grumpy but heroic steamsmith in the anime Kabaneri of the Iron Fortress. In the series, he wears a pair of glasses with the left lens clear, and the right lens green. With no explanation given. That’s not unusual in anime; fashionable asymmetry is a Thing, and it also shows up in samurai Kurusu’s outfit. Given the two end up fighting back to back, it could just be a style choice on the part of the artists.

But what’s the fun in that for a writer? It’s much more interesting if there are reasons for this odd little detail.

To create a good bit of headcanon, first make sure you know everything canon says about the detail in question. It saves you from embarrassing reviews later along the lines of, “but episode 7 clearly states that’s because of X!” Note, if this happens and you still like your explanation better, keep it. Just make an author’s note for your readers about this detail being AU. Or avid fans will be justifiably cranky.

Getting back to the case where a detail isn’t explained, so you create an explanation to make your writing easier. Such as Ikoma’s glasses. Here are the facts I assembled.

First, except for episode 12 (which is all kinds of action and Drama), Ikoma wears them most of the time. Times he doesn’t tend to be at night, indoors, or both. Second, in the few bits we see when he’s a child, he doesn’t wear them. Third, as far as I can tell from lens-glare effects, both sides do have lenses. It’s not a case of one lens being broken out, from the way light is portrayed glinting the left lens is there, just clear.

Put together, all of this implies that sometime after Ikoma’s home station fell, he developed light sensitivity in one eye. Several things might cause this, but two of the most obvious are some kind of eye disease… or a concussion messing with the nerves.

There are a lot of things that go boom in the Kabaneri ‘verse. Including – especially – suicide charges. One of which we know a young Ikoma used on his sister’s body.

Resulting headcanon: A much younger and slighter Ikoma used the charge and miscalculated, ending up thrown off balance enough to hit his head, causing an injury that affected his vision and led to the glasses.

Note, none of this affects canon details as seen in-series. It’s just a useful extra hook to hang stories on, especially if you’re trying to delve into the backstory of a character whose canon background is skimpy on details. Coming up with a few extra details to add that don’t change the basic story is a bit like extending the deck in the back of the house; if you’re careful, you can build new fics on top of it.

Which is what headcanon is for: making the original story make sense in your head, so you can write better, more interesting fics.

19 thoughts on “Writing Fanfic: Headcanon

  1. Non-writing fans will have head-cannon, too.

    Example: Star Trek.
    I do not “buy” that the Federation actually has all of humanity. We see Worf’s human brother being…more what I would expect a human with Star Trek resources to be.
    Which means the geeks must’ve gone Somewhere Else.

    Which would also explain why there’s hints of religion as remnants inside of Star Fleet, but no Human religions.

    And that’s where all the guys who made power suits and use anti-gravity to parkour all over the place are!

    Liked by 2 people

    1. “How Much for Just the Planet”. 🙂

      And now I’m picturing Space Amish with power suits quietly mining their asteroids and creating hollow worlds to farm and worship in as they see fit. The heck with the Federation.

      (They may even have a good trading relationship with the antigravity parkour nomads who partly fund their wandering ways by 3-D movies of the most gnarly stunts ever, dude.)

      Liked by 3 people

      1. I love that novel and I’d love to read a fanfiction of that.

        The parkour makes me think of Assassin’s Creed. They’re just living in Hollowed out Asteroids generations after game 3.

        🤔 Could they have Desmond in cryo stasis?

        Liked by 2 people

    2. My Trek headcanon: All those human-looking aliens with cultures obviously mimicking historical Terran cultures? Human colonies that claim to be alien in order to get better treatment from the Federation, who’d otherwise move in automatically, because humans are already part of the Federation.

      Code of Honor, for example. Really obvious group descended from wannabe-Wakandans. But TOS had the ‘coms and yangs’ world, the Roman Empire world, the world where children aged really slowly and then died at puberty, and probably others that don’t come immediately to mind.

      Let’s see, in season 1 of TNG there’s also Justice, where Shut Up Wesley steps on some flowers and gets sentenced to death for it (pity he got off, right?), Angel One with the planet of dominant women, the artsy-fartsy commune of Aldea, The Arsenal of Freedom that tells us M.A.D. superweapons are, like, totally bogus, duuuuuuude, and Symbiosis where one group is holding the other’s medication hostage.

      That’s six TNG season 1 episodes where Picard treats the ‘aliens’ with way more respect than he would a bunch of humans who need to be sent to reeducation camps to be enlightened.


      Liked by 3 people

    3. I too have Star Trek head canon. Specifically that Picard is the Federation equivalent of a city born, city raised, Ivory tower intellectual.

      He says, and even seems to believe, that humanity has moved beyond such things as greed, bigotry, and a number of other ills that are inherent to the human condition. Yet he himself displays that these things are not gone. That they are still part of the human condition. Most notably in First Contact, but also a number of other times during the series. And it’s also disproved by a lot of other people in both Next Generation and Deep Space Nine, and even early Voyager before the writing went completely off the rails.

      This leads into my next bit of headcanon. The Federation does have money. It’s more akin to the precious metals economy in my opinion and doesn’t make use of a hard, physical currency, but it does have money. Otherwise the Federation wouldn’t run. For every self-actualized intellectual who does it for the joy of it, you’ll find at least five people who would just sit around eating and watching space YouTube all day or even just sitting around reading fiction for enjoyment if there wasn’t some need to actually do work.

      I do think the basic necessities – on most of the developed worlds – are met in that you will be provided food, clothing, and shelter. But I think it would probably be very basic. Like bland clothing, functional, and precisely comfortable clothing with very few, if any, customization options. Similarly bland food – with the introduction of the replicator and Star Trek’s stupidly advanced medical technology – it would probably be a custom tailored nutrient drink or bar for food and then just water for drinking. And the shelter would probably be tiny and not quite cramped but very spartan. If it isn’t a barracks style dormitory. Basic needs met, and they almost certainly have public libraries and the like, but if you’re not working you’re not going to have the resources for anything personal.

      And we know that in Star Trek you can actually own your own starships and that there are private enterprises so there’s plenty of evidence that something like that could exist.

      Though on more general head canon stuff, I actually like it when stories or fictional universes leave enough room for head-canon to cover world building…though I don’t like it when that room is created by means of blatant plot holes and self-contradictory world building as has become increasingly the case with Star Trek and Star Wars (the Holdo Maneuver literally broke the Star Wars worldbuilding into tiny little pieces that had even less chance of being successfully being put back together than Humpty Dumpty). And Star Trek has pretty much thrown any ideas of continuity out the window with Discovery and then Picard. I know a lot of people hate JJ Abrams take on it, but at least his reboot was both an acknowledged alternate universe and functioned more or less within the realm of established Star Trek worldbuilding (though how Warp became Voyager-esque Transwarp…wait recovered scans and possibly pieces of the Narada’s Borg tech: New Headcanon accepted!).

      Sure the whole Supernova thing was kind of out there, but it actually could fit with some of the weird physics stuff. I personally like Star Trek Online’s idea where it occurred in a system far-ish away from Romulus and Remus, but that enemy action had caused it to propagate through subspace somehow and wipe out the Romulan home system and several other systems in similar range though I don’t think STO has established whether any were inhabited.

      Liked by 3 people

      1. I have a headcanon that there was a deleted bit while Holdo was turning her ship that explains that mess.

        What we didn’t see: Holdo throwing manual levers to disengage safeties that would have detected a mass in the immediate flight path and forced the drives to shut down.

        Also what we didn’t see: First Order idiots disregarding the ship as a possible threat because there’s no one aboard, even though they’re detecting hyperdrive spool up because it will auto shutdown in moments.

        But then it doesn’t shut down. And they realize too late that ship needs to be destroyed.

        But yes, that is otherwise a massive plothole for the entire series.


      2. The problem with the Holdo Maneuver goes all the way back to the first movie.

        The amount of damage done is such that you have to wonder why the Rebellion didn’t get a bunch of old ships and throw them at the Death Star instead of having to use the schematics/blueprints to find a tiny weakpoint and attack with the fighters. Hell just throwing an old heap of junk like the Falcon at the superlaser would be enough to mission kill the Death Star for months, if not years on end. Rinse and repeat as necessary to keep it out of commission until they can find some way of permanently destroying the station.

        If the Holdo Maneuver were at all possible prior to it being retconned into existence in Episode 8 then the Death Star while still a grave threat, would not have been as desperate a fight as it was in the original movie. It couldn’t have been.

        I mean hell, even if they wanted to do the trench run, they could have – and probably would have – done a hyperspace ram to knock the super laser out. The race would have been to destroy the Death Star before it a) retreated or b) got close enough to land troops and overwhelm the Rebellion through sheer numbers. But that wasn’t on the table. Because that wasn’t possible.


      3. That still wouldn’t have fixed it. While previous canon was not fully consistent on the exact details, it was consistent enough on “the appearance of ‘stretching’ as something ‘jumps to lightspeed’ is _not_ actually physically happening, it’s just an artifact of our minds not being able to process what we’re seeing”, combined with “stuff in hyperspace doesn’t actually affect stuff in the real world (which is why, among other things, there’s no way to track stuff in hyperspace directly)”.

        There _are_ safeties (you see them explained a couple times, with the events around the Corellian system when Centerpoint Station is used as a system-wide interdictor being the most detailed), but all they affect is “can you run the drive in a way that’s dangerous to _you only_?”, not “can you affect stuff outside your ship”. Specifically, the hyperdrive produces a field that holds the ship together while in hyperspace, but certain things in hyperspace _or in the real world_ stress that field and make the drive work harder (and overheat, if it has to work too hard). If the drive overheats too badly and burns out, you lose that field that’s holding your ship together, and standard _but acknowledge in-setting_ view is “and you end up scattered across hyperspace”, but it’s also acknowledged as unknown for sure _because there’s no effect in realspace_ other than the rare discovery of a fragment of a ship that was known to have gone into hyperspace and not come out where expected. All the Holdo manuever _should_ have done is “made the ship escape” or at _worst_ (assuming the FO ships included interdictor generators) was “destroy _itself_ but nothing else”.


      4. I too have Star Trek head canon. Specifically that Picard is the Federation equivalent of a city born, city raised, Ivory tower intellectual.

        :looks at it:


        :gets out stamp with 100% true and uses it:

        Head canon adopted.

        Liked by 1 person

      5. Thanks to replicators, the food and clothes can look/feel like anything you want– but we are shown a sort of barter system, and folks want the experience of going out to eat, that’s why Sisko’s dad has a restaurant. (For plot plausibility, you can even assume there’s a lot of basically black market, not illegal if you’re not caught, type stuff going on there.)

        Julian’s buddy who does the holodecks. That’s work.

        K, yeah, it could work basically like fanfiction does… which is what makes it hard to regulate. Especially when energy can let you make any physical object, and information is very cheap to send places, and it’s easy to duplicate the information for distribution.

        That kind of a system is sheer hell for people who aren’t good at Managing People.

        Liked by 1 person

  2. Sometimes, you just have to discard half of the canon, because it doesn’t make sense with the other half. Harry Potter is notorious for this, for example.

    A broader example would be any Japanese franchise that tries to do something set in ‘inspired by European medieval/renaissance/early-modern-era’. (Really anything Western/European prior to the Sexual Revolution.) Sailor-fuku-length skirts for the fanservice can end up being the least of their sins, although I was annoyed enough by it that in my ZnT fic the girls all wear skirts that are nearly ankle length, alongside other ‘no, this isn’t the 21st century, locally’ corrections. (Didn’t go full 17th century dozens of layers, because a noblewoman’s worth is in her magic rather than any sumptuary display of wealth. Plus if she has to fight she’ll want to be able to move.)

    Casual/public acceptance of yaoi and/or yuri in-setting being another, to the point where even in canon you might as well assume everyone is bi/gay until proven otherwise. I once read a statement where a Japanese producer said that he preferred scripting girl-girl relationships, because if it was guy-girl everyone would expect them to get together. I’m not sure why he thought everyone wouldn’t be expecting two girls to get together. (That’s even a social norm in Japan, albeit as a teenage ‘training relationship’ prior to marriage, which I’ve heard western LGBTQ celebrants complain about as insufficiently LGBTQ.)

    For some reason, I haven’t seen any fanfic do Roman notions of sexuality. That’d be an interesting one for a ‘culturally-isolated remnant in the modern world’, but maybe it’s too shocking for modern sensibilities.

    Still, the big problems in headcanon can come from the author of the franchise having ‘neat’ ideas that mess with what’s already established. Dumbledore being an evil manipulator stems directly from him not using options in the early books that didn’t exist until they were made up for later books. Likewise, a lot of what’s grimderp in Worm comes from people interpreting characters positively in early serial chapters, so Wildbow made sure in later chapters to clarify how depressingly misanthropic the whole setting was. Even to the point of erasing character development in order to drive home just how horrible a fan favorite was, proving her adopted mother was right about her all along.


    Liked by 1 person

    1. My understanding of the Japanese shipping thing is that they don’t have to have the girls “get together” because in most of those series, having the a boy/girl pairing get together is treated as effectively happening for life. It’s extremely rare – to the point I don’t think I’ve even heard of it happening – where we get a flash forward epilogue like the one from the Wonder Years where the main couple actually did get together…but then split up off screen and marry other people.

      Generally if there’s an epilogue the two will either be married with children (or expecting children), will be getting married in the epilogue, or one of them will have died leaving the other a widow(er).

      So in a story where there’s a lot of implied lesbian schoolgirls, if it’s Japanese, it’s highly unlikely that even they date, kiss, or even have sex, that it’s going to be considered an actual case of them “getting together,” unless the ending or the epilogue shows or tells us that those two girls are still together years down the line as adults.

      Cultures can be weird.

      Though can I say that I don’t think the LGBTQ+WTFUBBQ movement/culture is actually a good one that should be encouraged without being lynched?

      The idea that people who are Lesbian, Gay, or Bisexual should have equal rights under the law – up to and including giving them the same legal privileges as a heterosexual couple that is married according to the law – is one I do agree with. On the other hand holding them up as somehow being heroic or laudable or something to aspire to be because of something that the movement has been claiming (and some of the science I’ve seen has backed up) that your sexuality is not something you choose so much as something that develops organically based on genetic predisposition and your environment growing up with the vast, vast majority being heterosexual – or to use their term heteronormative – is in my opinion very disruptive and disingenuous.

      Further, given my understanding of what it actually means to be transexual, I don’t think it should be classified the same as being Lesbian, Gay, or Bisexual. Because to my understanding actual transexuals have pretty severe body dysphoria which is an actual mental disorder. It has nothing to do with who you find sexually attractive, and everything to do with some pretty severe body issues that can and does drive people to kill themselves.

      …and the less said about everything covered by the +WTFBBQ the better.

      Liked by 1 person

      1. Though can I say that I don’t think the LGBTQ+WTFUBBQ movement/culture is actually a good one that should be encouraged without being lynched?

        Given the number of predators that have used it*, and the number of times I have watched people flatly say “this and that is obvious abusive grooming behavior, but in this case it’s OK because shut up”, I sure won’t disagree.

        The abuse Moira Greyland has suffered for speaking out to stop violent molestation of young boys is more than enough evidence that judging actions by “movement,” rather than objective worthiness, is a grave failure.

        *know issue of sub-cultures; the smaller it is, and the more the members feel under pressure, the easier it is to be hijacked.

        Liked by 2 people

      2. I’m working on excuses that will sound plausibly ‘woke’, in the event that someone ever asks ‘why no this or that?’ – I like ‘I’d rather let an authentic representative reap the rewards of diversity and inclusion’ – but the main one is that I don’t like promoting groups that double down on giving cover to predators.

        Such as, for example, calling Milo a pedo for outing pedos.


        Liked by 2 people

  3. When I’m reading fanfiction, anything directly stated supersedes the original canon.
    I just assume its and AU, or for plot reasons, and I’d much rather read a well put-together story than one that adheres to canon particularly well.

    The problem arises with indirect implications.
    The original canon may not explicitly state that B exists because of A, but they connect well enough together that I assumed they were related.
    Then a fanfiction author keeps B, but overrides A… and things don’t fit together quite so well.

    When I’m reading a story as it’s being written, it’s always awkward to try and point that out.
    I don’t want to assume they made a mistake, but I can see a huge plot hole coming in the future.

    On the one hand, they might have some amazing idea for how it will shift.
    On the other hand, they might have overlooked the detail and write themselves into a corner.

    Liked by 1 person

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