How to construct Alternate Universes that work as fanfic
by Rat Creature
1. Why some (even weird) AUs work as fanfic, and others don't
In this and other forums there are regularly discussions about the merits and pitfalls of "Alternate Universe" fanfic. Usually the focal point of those discussions is how far one can diverge from canon without the story ceasing to be fanfic that is still true to its source, and thus to its nature as fanfic opposed to original fiction -- sometimes with the implied charges that something is only thinly "disguising" as fanfic in order to "trick" and attract the readers. At first the theory behind this seems reasonable: fanfic is about the source, so the more you change the source, the more you drift away, until the connection can't be found anymore, and the story doesn't work as fanfic any longer.
But this simple theory doesn't fit the data. There are AUs which change very little, say the profession of the main characters, and don't work as fanfic anymore, whereas there are others, which change the species of the same characters (and with it a whole lot of other things among those the profession) and succeed as fanfic, and are perfectly recognizable as such to everybody who knows the source. Why does this happen? Are these rare exceptions, only due to totally exceptional writing? I don't think so.
Somehow this focus on whether the adherence to canon in fact or spirit is still sufficient for a story to count as "fanfic", misses the essence of the AU genre. In a nutshell the main point of fanfic is to explore the universe and/or characters of a source, taking that source into new or familiar directions with canon as a -- however vaguely defined -- starting point. What defines AUs as a genre is that they explore the canon universe and/or characters by breaking or diverging from canon deliberately. Hence the crucial point of success or failure for an AU is not to what extent it adheres to canon, but how it diverges. Which isn't the same just said inverse, since the focus and the way to look at differences from canon is very different in those approaches. This may seem simple and self-evident, but is still of fundamental importance when looking at AUs.
Even widely diverging AUs are still genuine fanfic, because their point of reference in the eyes of the author and the reader is still canon. The link between an AU and its source is not so much provided by their resemblance as by the nature of their differences. The potential problems of AUs don't simply arise because an author "went too far from canon", making her story somehow "break" its link to the source.
The problems that many perceive as an AU bearing no resemblance to the source, are in my opinion most often not caused by the radicalness of the premise or the distance between the AU and its source, but by the quality of writing -- which BTW can easily cause non-AU stories to bear no resemblance as well, though sometimes in different ways. And the fundamental problems of some AUs are usually not caused by the lack of some random writing qualities, but more specifically by the author lacking awareness of the kind of divergence from canon she wants, and of the goals she wants to achieve by those changes.
For an AU to be successful this awareness is essential, because the point of AUs is to explore canon by diverging from it. This part of their relation to the source defines them as AU. Only when the divergence -- sometimes radical, sometimes small -- is pointless and not related to an exploration of the source, the AU will fail to work as fanfic. Even though the link between the AU and the canon is still there, the reader can't make sense of why this divergence was chosen, what the point of it all is. So the question of divergence is never really one of "how far" but always one of "how well" and "how deliberate". If there are compelling reasons to change canon or even characterization in a certain way, the AU will be successful in exploring canon and characterization, and thus successful as fanfic, even if it is diverging widely. However if the changes are arbitrarily or pointless the AU will fail, even if the changes are small.
So it is essential to construct the divergence in a way that leads to an exploration of canon issues. IMO that can happen by changes to mythology, setting, characterization, universe rules, and a number of other things. However there are certain key elements to a source whose inclusion (either in their original form, as a changed element, or as an explicitly explored absence) is to some essential for the relation to canon, a simple omission of those elements may make exploration of other canon aspects pointless. Those key elements, the core of a source, are not the same for each fan, though there is considerable overlap in some fandoms. For me those key elements are for example in TS the existence of heightened senses with Jim Ellison as a sentinel, in SW:TPM the Jedi and the existence of the Force, in XF a widespread conspiracy and paranoid mood. For others the key elements could differ, like in TS a special connection between Jim and Blair based on whatever, in SW:TPM an order of warriors with masters and apprentices (no Force or Jedi trappings required), in XF the existence of alien abductions. When an AU does not deal with something that is such a key element for part of the audience, but simply omits it, it won't work as fanfic for those, regardless of other connections to the source.
2. What kind of AUs there are, and how they differ
The lack of awareness concerning the kind and the goal of the changes to the source, that is responsible for the failure of some AUs, is partly caused by the category "Alternate Universe" lumping together extremely different kinds of divergences from canon. The only thing they have in common is the basic principle of deliberate changes to the source. That is why stories written while a series is still in production and later contradicted by canon are not counted as AU: Their divergence from the source's canon wasn't a planned way to explore it, but merely "coincidence".
But beyond that AUs have little in common. Depending on what kind of divergence serves what purpose, AUs can be divided into several sub-genres. Those have different strengths and weaknesses, and also put a different emphasis on exploring the aspects of a canon divergence. When choosing to explore a canon-breaking idea, the success always depends on whether the type and the scope of the divergence, as well as the special perspective of the sub-genre, provide an interesting view on the canon characters and universe, because ultimately the readers expect an exploration of those in fanfic. The consideration of what is gained and what is lost when changing the canon into an AU, and if that trade is worthwhile to readers hooked by the original, should always be part of the planning of an AU.
There are several basic types of "Alternate Universes" (in the broad sense of AU as genre): Stories that diverge at a certain point in time from the canon universe and don't change the rules of that universe. All of those you could call 'Point of Divergence' (PoD) stories. This point of divergence can be during or before canon.
There are two kinds of PoD stories:
The ones which focus primarily on one or several main characters' lives, where the universe itself doesn't change much, but their individual lives change more or less drastically, you could call them Alternate Reality (AR) for distinction. ("Reality" because none of the the 'real' universe's rules have been bent or broken, nor have the universe 'outside' characters' lives really changed). In character centered universes (or stories) there are usually a couple of standard points of divergence in fanfic for each fandom, mostly employed to 'fix' a canon fact that some subgroups of the fandom don't like. Those fix-its can become stale after a while: what if RayV didn't choose his undercover job, Qui-Gong wasn't dead, Blair didn't renounce his dissertation etc. But the AR genre as a whole still has the most fascinating possibilities to explore how a single action can change and influence a person's life.
There is another kind of PoD story whose focus isn't so much a change of character, but rather of universe and/or mythology. It explores the impact the characters' actions have on the universe and history as a whole. Those PoD stories focus on the change of the universe and society rather than on individual characters' lives, though those lives might have changed equally radical. Those you could call Alternate History (AH), like the equivalent pro-fic genre. There are also a couple very typical PoDs, and most often they are found in fandoms with at least a partial focus on an encompassing mythology: what if the Sith had won instead of the Jedi, what if the Consortium had succeeded etc. Those stories are especially suited to explore how one person's actions can forever change the basic structure of an universe, or how one historical event can change the characters' lives. This kind of AH is also found inside canon, in what-if episodes, for example the Buffy episode The Wish.
It is also possible to write an AH, where the universe changed before the main characters were born, like "transferring" modern day characters into one of the 'classical' types AHs, like how would they live if the Civil War had been ended differently, if Kennedy hadn't been shot, etc. However the chances of success are higher if the change is connected to the universe and its mythology somehow, because then the divergence will make more sense to the readers, and involve them to a larger extent. For example in an X-Files AH where a different end to the Civil War was intended one could link this change to conspiracy involving aliens, who meddled with US or world politics earlier than in canon, e.g. what if Roswell had been 1840...
The difference between whether a story is an AR or an AH isn't so much determined by the kind of PoD it chooses, but rather by its focus. A "Qui-Gong is alive" story could be an AH if it focuses on the impact this has longterm on the SW universe, or an AR if the focus is that Qui-Gong and Obi-Wan find out that they love each other.
The other type of Alternate Universe are stories that are not PoDs, but simply state that the universe isn't the one we know, without giving any history or reasons for it. Those you could call Alternate Universes in the narrow sense.
The three basic ways to create an AU in the narrow sense are to put the characters into a different universe (e.g. transplanting the characters into space, into the Middle Ages etc.) , to change the fundamental rules of a universe (e.g. everything is like in canon, just magic works), or to change something about a character fundamentally without a certain point of divergence (e.g. everything is like in canon just character X is a werewolf). Depending on the canon universe changing one of those things will make other changes necessary to preserve internal consistency, e.g. making Mulder a werewolf wouldn't require universe rules to change, since they exist in XF, whereas making Jim Ellison a were-panther would definitely change universe rules. But if one change is supposed to be the focus, that will impact the story, so there are still AUs which are primarily about changes of either setting, rules, or character.
Of course it is also possible to give the change of several parameters at once equal attention, but the less clearly defined the extent and nature of the initial changes is, the more likely it is that they loose their function in exploring canon, causing the AU eventually to fail. So keeping the initial changes simple and clearly defined increases the chances of a successful AU, i.e. successful as fanfic that explores canon rather than disregarding it without reason. This isn't the same however as the "surface" of the AU not being wildly different from the source, it only is about the clarity and justification of the initial premise.
One special type of the 'transplanting AU' is the fusion x-over, which merges the characters of one show with the universe of another show. Unlike most x-overs fusions focus on one set of characters (though sometimes characters of the other universe are also mentioned), and explore a lot of cool possibilities of both universes and character development without the pitfalls of complete 'canon-merging' x-overs. It also has the advantage that the numerous changes to both character and universe which are necessary to construct 'transplanting AUs' in general, as character and background are closely linked, are cushioned by the fact that the universe is already familiar, and at least for fans of that universe worth exploring in its own right. Fusions can be both very AUish or quite canonical, depending on which shows are 'fused'. TS/SW with TS characters in the SW universe would be very much on the AUish end of the spectrum, but the premise of setting TS in the X-Files universe (without Jim and Blair meeting Mulder and Scully) would have a more subtle, though still severe, impact and would set the story closer to the canon side. Especially suitable for fusions are RPG universes, which can give fascinating results, though the most known variant of this model, i.e. fusion with high fantasy universes, is somewhat overused. Still there are great possibilities, e.g. how would dS, TS, or Homicide look like in a SteamPunk universe? (SteamPunk combines the mood of cyberpunk with an alternate Industrial Age, where computers and everything else runs on steam power).
The last, somewhat frowned upon variant, is the AU that changes characterization -- not just some character's "attributes", e.g. profession, species (e.g. human,vampire, were-animal...), health etc., though admittedly the line between "attribute" and "characterization" is extremely fuzzy -- without giving the definite history of a canon PoD for it. You could call those "Alternate Characterization", but this term has a negative ring to it which I don't intend.
In AU discussions a common opinion is that the characterization has to be fundamentally the same as in canon for something to count as fanfic, but in my opinion AUs -- as fanfic that explores canon by breaking it deliberately -- can still work, even as "Alternate Characterization" AUs, as long as their goals and relations to canon are still clear, even though they are admittedly very hard to pull off well. They have the best chances to succeed if only one character is changed, and they then explore how the others cope. That works best if the character who is supposed to be different tricked the others before or was forced to hide his true self, so that the reader adjusts with the other characters. Usually it is a story line like character X is really a villain, villain Y has decent motives after all, or the secret of Z finally comes to light. They can be fascinating views, sometimes, and turning villains decent seems to be more popular than vice versa, but turning heroes into victims, e.g. by giving them drug abuse, or severe psychological problems, without basing it in any way on canon, follows closely behind in popularity. There are however other examples for this, like Debra Fran Bakers Queen!Jim stories.  Generally all types can be very similar to canon, or very different. That just depends on what point of divergence one chooses, what universe fact, rule or setting is changed, which shows are merged, or which character is changed to what extent respectively.
3. Why this classification is useful when constructing an AU
This classification helps to develop a clear strategy, and get a better grip of the divergence, when considering an AU, or when evaluating the success or failure of one. To illustrate this, I'll look at examples of possible TS AUs, all starting with a "cool idea" that will break radical from canon, and show which realizations of those ideas will have a chance to succeed as fanfic and which are likely to fail.
a. A fundamental change to one of the basic characterization traits of the main character:
The core divergence from canon is supposed to let Jim Ellison be more accepting of his sentinel senses, not to struggle against them as he does in canon.
When one looks at this divergence considering the "trade off" from a canon viewpoint, it is problematic because of two things; first it changes a fundamental character trait, that makes Jim Ellison complex and interesting, and it robs the original of a main source of conflict. But at the same time those changes are also interesting because they don't change the character randomly, because they are closely related to the mythology of the series. Still the pitfall of a flat cardboard cut-out "primal sentinel" characterization will have to be watched, at least in some kinds of realizations.
How can the classification help to decide what is the best way to explore this basic AU divergence idea? Lets sort through it:
First possibility is a PoD story. With an AR several points of divergence could lead to the desired result, more or less close to canon, depending on the PoD: Jim could simply retain more of his experience in the Temple of Sentinels, undergoing a more radical transformation than in canon. Jim could have stayed MIA in Peru, living there longer than in canon, and finally adopting fully the Chopec culture and his role as the tribe's sentinel. An example for this is Jungles of Peru by Jaguar. Going even further back, maybe Jim's father could have institutionalized him as a child, so that he while he didn't repress his abilities, and accepted them as integral part of himself, though he sees them as madness, living through institutionalization with maybe more or less prolonged breaks.
PoDs for AHs with this divergence are harder to come by. Possible are circumstances which turn the existence of sentinels into public knowledge well before Jim Ellison's birth, a kind of apocalypse during his life time or before which forces him to accept his senses and position as sentinel fully to just to survive etc.
But some of those PoDs change a lot, and might not be the best way to explore the originally intended divergence, rather it could turn out to be a side effect. If the character change is supposed to stay the focus the most obvious PoD would the least disruptive to the rest of the universe, e.g. the temple of sentinels. OTOH one of the other PoDs can be interesting enough in itself or give additional credibility to the change of characterization, to warrant a split of focus from the initial divergence.
Second possibility is writing an AU in the narrow sense. With a change of setting, i.e. a transplanting AU, any society which believably could know and utilize sentinels could achieve the desired divergence, e.g. a 'primitive' tribe. The Middle Ages might be a bad idea, since Jim might be considered possessed... But the problem with the choice of a change of setting to realize the chosen divergence is, that the change of setting is neither connected directly to the divergence nor does it explore canon itself, so the changes can easily seem arbitrary. The special choice of a fusion could add interest into the changed setting, e.g. a very successful example of a similar character change through a fusion is the TS/SG-1 story Destiny's Bond by Wolfling.
It is harder to find a fitting change of universe rules. One possibility would be to proclaim 'sentinel instincts' which are much more pronounced than in canon, to construct a set of sentinel behaviors that would lead to Jim Ellison being more accepting of his senses. However as pointed out above this is closer to the danger of a uniform 'cardboard' sentinel. And unless you include other sentinels into the story, it could seem as if just one character has been changed without good reason, and it might not be obvious that it is a deliberate change of a universe rule instead of arbitrary bad non-canon characterization. Still in TS this scenario isn't rare, and not even always called AU, because sentinel instincts exist in canon, and hence the change of rules into AU territory is gradual and debatable.
Obviously the change of a character attribute would be the most direct way to go in this AU, but it isn't such an obvious change as something like "werewolf", so it might come across just as a slightly off characterization. That there is no change in the universe or character history, when the change of character attribute isn't necessarily noticeable at first glance, will also make it harder to explore the divergence, which isn't the best way to go about an AU as I pointed out previously. Also giving neither a reason, nor a history for character changes isn't very popular.
b. A change to a fundamental universe rule:
Magic is supposed to work.
This one is tricky, because it may be a cool idea to have magic work in the TS universe, but it has no direct connection to the source. There is no obvious, compelling reason why this premise should lead to a promising exploration of the source. On the contrary, a main fascination of the TS premise is that while there are heightened senses not too much other stuff is weird, giving the universe a credibility that it would otherwise lack. So the first step has to be to find an interesting way to connect this magic premise to canon, the second to develop a magic system that isn't totally out of sync with the canon and atmosphere of the show.
Obviously PoD stories aren't a possibility, since there is no way from canon cascade, past or present, leading to the "magic works" premise.
That leaves AUs in the narrow sense. So how about some kind of transplanting AU? One could easily choose or construct a universe with magic, however the problem of connecting the divergence to the desired exploration of the source remains. One possibility is literally transplanting them, i.e. the "rabbit hole" variant, where somehow the characters as we know them are transported into another universe, so that the story could explore the canon characters' reactions to magic being common. But this transport is an extremely obvious plot device, likely to irritate readers. And canon TS isn't suited to that kind of deus ex machina, so it is unlikely that it would work as well as the XF fanfic Magician series by Suzanne Bickerstaffe and Jennifer Lyon. It remains making the TS characters "native" to the magic universe, but for that 'transplanting' to somewhere not present-day Cascade would change more things than necessary for the chosen divergence, letting the reader wonder about the point of it all and loosing interest in the scenario.
That leaves changing present-day Cascade into a universe where magic works and connecting this to the canon source in an interesting way. One possibility is to make magic work, but not be acknowledged by the majority and to change the sentinel mythology so that it is incorporated into the magic system. That leaves most of the TS canon events and reactions intact but still makes it plausible that Jim and Blair 'discover' the magic, and lets the readers explore and recognize the magic gradually along with the main characters. D.L. Witherspoon does that quite successfully in her Supernatural and GatesOfHell series. Though she lost a lot of my interest when she gave Jim more and more powers, and introduced ever more supernatural phenomena, because there started to be too many different changes, that weren't sufficiently motivated for me, e.g. I'd rather remained in a universe where Voodoo works, Jim has the ability to talk with the dead (she introduced that long before it appeared on the show), and some expanded sensory powers like in the first GoH, than to add archangels, Lilith, Hell, etc. into the mix.
Another possibility is to make magic widely known, though maybe illegal, but not sentinel senses. That would lead to interesting reactions by Jim when discovering his senses: he could assume himself being cursed, maybe suspecting Sandburg when he's approached by the "witch-doctor punk"; maybe he believes Sandburg, but they get under suspicion/prosecuted for the use of illegal magic in police work...
c. Removing a key element
What if Jim Ellison wasn't a sentinel?
Obviously this is an AU that's very hard to do, at least when it is done explicitly (stories not labeled AU where the reader never notices that he has sentinel senses aren't that rare). The senses are what makes TS interesting and different, and, as explained above, are a core element that constitutes the series. So why would any fans of the source be interested if it's taken away? However there are ways to get new and interesting looks on canon characters and universe by this. As a PoD you could explore in AR scenarios how Ellison would cope if he hadn't regained his abilities in Warriors. What would have done that to his psyche, to his friendship to Blair, how would Blair deal with that situation, how would Blair (and Jim) react to Barnes later, how would the events of S2 look like...
I can't think of an AH scenario, although similar changes could work as an AH in universes with a more encompassing mythology, e.g. would the consortium have won had they not kidnapped Mulder's sister, would the Sith have won if Obi-Wan wasn't a Jedi etc.
When choosing an AU where Jim never had sentinel senses, it will get more difficult. Also those could be only realized by an AU that without explanation changes a character attribute or a universe rule, since transplanting won't help here. Changing a character attribute would be just "taking" Jim's abilities, changing universe rules would be something like eliminating all sentinel senses.
The main obstacle remains keeping this change related to interesting TS things. Since most likely the two main characters wouldn't have met without the senses in the present-day Cascade setting, one faces either the problem that there is no friendship like in canon or that one has to change setting and events along with the defining element of characterization, which makes it nearly impossible to get an interesting spin on canon from the result, thus leading the reader to wonder why this way of breaking canon was chosen.
So if the setting isn't changed and the AU takes "just" Jim's senses, an interesting question is how Blair's life would develop. Would he stick with the sentinel topic, would he still meet Alex somehow, would he maybe meet Jim through the police's confrontation with Alex?
If the setting is changed and another way of the characters' encounter is managed, there could be the attempt to do a "friendship" story, but even if there is, it would hardly give interesting views on the core theme, at least not for those fans who, like me, define TS through the senses. However it might work perfectly well as fanfic for those who define TS through the friendship.
When taking away sentinel senses in general from the universe the only way I see to connect it in an interesting way to TS canon would be to keep the premise that for the current level of development in the TS universe (which looks similar to ours) the existence of sentinels is, or had been at a previous point, necessary, so that the AU would explore how the world would look like had they never existed. If one can come up with a reasonable PoD far enough in the past which explained the disappearance of all sentinels, that scenario could be written also as an AH. The main difficulty with that AU scenario would be to convince the readers that the changes can be really traced to the absence of sentinels, and aren't just random. A tough task, since from our everyday experience we are convinced that we didn't need sentinels to reach the current state of our world.
4. And the purpose of all this?
I really like AUs. Even lots of AUs that are at first glance far removed from canon. OTOH in non-AU fiction adherence to canon is very important to me. I always had problems to reconcile those seemingly incongruous preferences. Then I noticed that many who really like canon-like stories, ask for less radical AUs, which can be seen in Lena W.'s symposium column for example, but for me that couldn't be the solution to the problem of AU construction, since I like some far fetched AUs, but not others. My goal was to show that there can and should be AUs that are radically different, but that their difference from canon needs to make sense in the framework the show gives to us.