Foundations of the story
Who is Dr. Gotham?
I remember reading one of the Batman stories in the late 1970's that briefly featured a character named 'Doctor Gotham', and that story was a reprint of an earlier story from the 1950's or possibly earlier. The memory of the character is vague, save that the Gotham City that it took place on was more the rolling hills of Gotham one than any of the more modern metropolitan settings. Basically my memory serves up a Gotham that could have been a small college town (or small city) in the semi-rural Northeastern US. After that I have little or no memory of the character save that he may have been slightly affiliated with the supernatural, and that he wasn't exactly a villain, nor a hero, nor fit into any real category. He was on a street lined with shops and his was a simple shop of curiosities and similar items. It is from this vaguest of memories that I create a more modern version of Dr. Gotham.
Gotham City, itself, has parts of the Cthulhu Mythos attached to it via Arkham (the town) and its famous Asylum. This, too, is a supernatural set of works done in an Open Use format for writers, so that the mythos can be re-purposed to various settings. In the previous story I put together a Gotham City with strong hints of the supernatural about it, particularly the Ghost Trains, and that seemed to fit with the concept of a Dr. Gotham and even some of the Cthulhoid Mythos and its extensions. Taking these things as a whole this started to shape just who Dr. Gotham is, and we get hints of that as the story continues and it fleshes out the character and the world view that goes with him.
How old is Dr. Gotham? I have no idea but there are time limits that require he be human (not just Cthulhoid Mythos humanoid, but actually human) and has lasted in the area for a long time. This presses his origins back into history and beyond recorded history and as the region of Gotham was covered by glaciers at one point his presence can be said to date from the first of the proto-Europeans that were in that region (roughly from the Delmarva Peninsula up to the terminal moraine of Long Island) circa 10,000 years ago. He became a servant of what would come to be known as the Gotham Islands then Gotham Town and, finally, Gotham City although it was not called Gotham until Dutch and English settlers got to it in the 17th century.
How did he get to be in the state he is in? I leave that properly shrouded in history, but it is safe to say that when the man who would become Dr. Gotham became a servant of that power that would become the Gotham Islands, he was granted or garnered some abilities not available to the rest of humanity. That power that is Gotham, is not one native to our universe but is a lesser being of primal Chaos. Such beings are not in the top rank of Chaos, they are not of the Tiamat sort nor of her first or second sets of secondary Chaos children. Those children we think of as gods, demons and have some of the nastiest of the Cthulhoid Mythos beings in them. The second set ranges all the way from the Shoggoths to Cthulhu to Shub-Nigguroth. Only Azathoth is not in that as it is Primal Chaos. As a lesser being that power which is Gotham cannot create a universe for itself, it does not have the vast swath of power that a Cthulhu or Yog-Sothoth has, and only starts to hit into the lesser avatars and harbingers like Nyarlathotep in power category. Thus Gotham only has a few tricks up its sleeve and as it is not really familiar with this universe that came with Tiamat, it needs a way to get some of the perception of it that are not within its powers. Thus, Dr. Gotham becomes that one and is granted some capabilities but is, basically, left to his own devices.
With this sort of background a sudden skip of a few decades for Dr. Gotham is one of those chaotic things that happens in the course of his life, save that it takes him from early modern times of the 1930's all the way into the 1980's. Having already seen much over 10,000 years, this is not such a huge problem for him as the actual demographics of the region haven't changed much in over a century and the geography only changes at a very, very slow rate. He recovers quickly because of what Gotham is to him and that Gotham speaks to him in ways we cannot see nor hear. Being a servant of Gotham will do that to a person, and Dr. Gotham adjusts because he is in tune with how the city and its people work and feel. These are imprecise terms, at best, but are a major part of how he lives his life.
What that background doesn't get him is exacting information, and he depends on events to move in such a way to bring information he needs to him over time. From his perspective this always works: he had early Amerind knowledge after the catastrophe circa 9,000 years ago and the remnant population that started to fuse with the more Asian natives then came back his way, he has had contact with early Vikings to put him in tune with what was going on in the northern areas of Europe, then came the Spanish, Dutch, English and various others. For those the islands that would become Gotham Islands served as a place to inhabit, rest, get fresh water, restock, resupply... it became a minor trade center and was relatively major until New York was established and began to prosper in Colonial times. To interact with this changing cultural landscape he has run a business, a trading store by and large, that then became a minor curiosity shop. In keeping with being a servant meant to see and understand these changes, he moved from place to place within the environs of the Gotham Islands and that became a function of the place that would be Gotham City.
After all of this what comes out is a man who is in many ways more than a man, but also constrained by the role and position he has gotten. He cannot stray far from Gotham due to its hold on him, which makes him far more understandable and yet also more enigmatic. He must depend on the travelers and information that flows into Gotham City and that while enhanced by the modern age is, in many ways, not as thorough as when it was travelers who had to tell what they had seen and heard on their own. What we would consider marvels of modern communication he would see more as clutter, however, as they are merely conduits of information and that information that he needs will get his attention. Thus it doesn't matter if it is word of mouth, books, magazines, newspapers, radio or, now, television that conveys the information to him as, in his experience, he gets what he needs in the way of information even if he isn't always able to discern what it means to him. For that he does research and consults various methods to help recast information to help it speak to him more clearly. What we may see as nonsense is, to Dr. Gotham, a vital way to order information and reason through it.
No matter what his personality started out like, it would be reshaped by how events move around him and how he had come to perceive them. As he garnered more information, like that of the Cthulhoid Mythos, as an example, his perceptions of himself and the world would necessarily change. Those denizens would show up before the re-population of the Northeast by humans and he would also get to know of these beings, if not meet them directly as well. From that he garners different associations across a range of peoples known and unknown to the reader, and yet they will also shape his outlook over the centuries. For all of that he is still mortal, not invulnerable and can be prone to those things that will ail the flesh, even if his recuperative abilities also allow him to overcome many if not all of them.
* * *
The Mythos as Presented.
When writing about a universe that has a deep background to it there is a necessary requirement to get to some basis for how it came about. Mythology is employed to put such a start point into human-renderable terms as we are not sufficiently set up to the basis for such a universe we then look to non-human rationale for such a beginning. As presented at various points in the Batman canon, the world of the Batman (if not the DC Universe) is that which has a Judeo-Christian belief system that has come out of earlier polytheistic traditions. Captain Marvel is, in particular, rooted in this transformation of systems so that he can be both man and god via the combination of different mythic traditions. The Amazons are also a remnant of earlier traditions, and are not the only example of this in the expanded DC Universe. From God to Satan and various devils, demons and angels, the DC Universe demonstrates a deep rooting in the latter part of the transformation from polytheistic tradition to a monotheistic basis. From the perspective of the Batman works, however, religion and mythology are not primary concerns of the general tone and tenor of what the Batman does. That he has morals and ethics based in that tradition is without any doubt and is demonstrated multiple times throughout the entire sweep of the canon, including those parts that have been removed by later events (ex. Crisis on Infinite Earths).
This must be a given and a necessary point of continuity so as to create a proper setting for Gotham City and its environs. What happened early on (as they were contemporaneous) was the infusion of the Cthulhoid Mythos environs into the Batman setting. Very few other comics in the DC Universe even mention this, and yet because of its basis and setting the Cthulhu Mythos must of necessity drag Gotham City into the Northeastern US. Other settings are possible, of course, but few mention Arkham, and the name of Gotham, itself, while having been applied to New York City is one that is brought by early settlers from Britain infused with some Dutch background. This rationale used in the first story continues in this story, which now allows for the proper shifting of the generally modern monotheistic tradition coming from a historical polytheistic one, to be made into a blended situation through the addition of an older mythic canon. When writing of a Gotham that has this situation attention must be paid to the distance between 'Lovecraft Country' which is from the lower parts of VT and NH, through northern MA and to the coast north of Boston, and the overland distance to Long Island Sound. In fact the nautical distance going around Cape Cod must also be taken into account due to those denizens of the Cthulhu mythos structure. Gotham does not have the problems of those along the Miskatonic River from Arkham to Innsmouth to Kingsport, but they do get some of the feel of personages like Charles Dexter Ward of which his singular case can be a representative of a much wider, though less noteworthy, set of cases that would show up elsewhere in the region.
From that brings the analog of the Gotham River system which isn't the Miskatonic River (although it does have some underground flow structures here and there) and would also serve as a set of formulary points for scenes typically described in the Cthulhu mythos throughout New England, NY, PA and NJ and moving over the St. Lawrence into parts of Canada. Gotham City is no Innsmouth or Kingsport, then, but has contact and influences with those settlements either overland or by sea, and the second becomes more important as early travelers to the region during precolonial times that were blown off course to the north would then either seek Boston or go further along the coast to the trade center that would be New Amsterdam (New York). Gotham is a waypoint between those two and got much of the stories (if not beings) that go along with such trade. Once swampy islands, Gotham becomes two larger islands with more than just a set of hills and a shore ridge line, but an actual port worth going to for a time. Like the settlements along the Miskatonic River, those at the outflow of the Gotham River would have similar backgrounds, stories and inhabitants, and not just the human ones, either. Yet Gotham is darkly its own environment that is not just a blending of something between Innsmouth and New York City: it is no Providence nor Hartford but something quite different.
Infusing two mythos groups together then starts to put a longer back story into the Gotham City setting that is unique unto itself. Yet for all the exploration of that mythos (which goes back before the beginning of life on Earth) it has only the vaguest of starts to it from Azathoth, and while that Primal Chaos at the center of all things (and yet close to none of it) can generate up such a universe there is a rationality given by not just Batman but the whole of Gotham City that is difficult to image from that source of beginnings without modification. To get a firmer grasp of this time and to put into it that rationality requires going through the other side of the mythos, the Judeo-Christian side. At its basis this tradition grew out of a polytheistic one that is represented in Mesopotamia.
When the creation myth of this line is examined it gets multiple starts to it, which is reflected in short in Genesis. There are two separate parts to it that get put together: speaking the Word and then separating the heavens and the Earth. These two pieces have counterparts to them in the mythos best typified by Marduk (although going through Ea and Enlil previously), as it puts a mythological state together that does not have an Earth as its starting point. This is fascinating on multiple levels, but is one that can be put into concordance with the later Cthulhoid traditions in that while Azathoth can spit out beings, universes and such, they are not well formed or described (and many go insane in close orbit to Azathoth) and only gain definition far after being put into some form that exists. At its start, then, the universe described at the very start of the canon that begins with Marduk's predecessors is one that has a Prime Chaos being as the holder of the space spat out by Azathoth and then gets outside visitors (not necessarily demonic, but other chaos beings) who seek to join in this new space with its ruler.
This now begins the process of generating, at first, the Gods and then the Monsters. The first husband of Tiamat, the ruler of this realm, wants children and then is horrified that they will be more powerful than he is. He wants them killed before they are born and Tiamat refuses to do so as she has motherly instincts as part of her character. From this the Gods are born, their father defeated and then half of the Gods go to work for their mother and the other half do not. Tiamat sets that half of the Gods that stay with her to go to work doing... something... here is a major problem and opportunity point in the depths of the Judeo-Christian tradition that is fascinating. There is no world, there is no ground, there are no seas, there is (presumably) space of some sort, but what sort of work can half of the Gods actually do?
The secondary part of the Tiamat story comes to the forefront as they are physical objects that were, presumably, generated up when Tiamat came into being: the Tablets of Destiny. These are things that describe not only the immediate future but far future of... well... everything, Tiamat included. This is a predestination part of this mythos that really, isn't one that should coincide too well with the Cthulhoid mythos, and yet it does. The second action of Genesis describes the parting of the Earth and the Seas and the creation of all things. The universe itself was brought into complete being by a word (which I call a Word of Power). This shows up with Tiamat's second husband who wants access to the Tablets so he can see what sort of children they really should have. He is also a Chaos being, but of lesser rank than Tiamat as he must come to her place: he doesn't have his own. After reading the Tablets he wants: Monsters. Demons, devils and just all sorts of creatures. All of these are ALSO set to work, again we don't know what they are doing, and this horrifies the half of the Gods that decided to kick back someplace else. They now realize that their kin are being enslaved and perhaps worse being done to them by the Monsters. They want an end to that, but none of them are strong enough to contest against Tiamat (who now has a plethora of children to adore, not just a few). To stop that the Gods realize that if they are to have any chance of rescuing their brothers and sisters, they must put all their power into one of them along with all the gifts of power they have. That one is Marduk (in later traditions) and he sets out with nascent powers and some sort of beast to start bringing down the old way of things.
At some point Marduk stumbles across the Word of Power and uses that against his father, killing him instantly. With that word Marduk is able to free his brothers and sisters while he, and his siblings confront the Monsters and their step-father. The step-father knows he is not immune to the Word and betrays Tiamat by showing where weapons to kill her have been made. Marduk takes those, kills his mother and separates her body into the Earth and the Heavens. With the Tablets under his control he kills his step-father and creates Man so that his soul may live and die billions upon billions of times forever in torment by being broken up. This now gets you to the basis of the Judeo-Christian mythology and the Cthulhoid mythos as the Monsters are obviously different orders of Chaos spawn and some of them God-like in their power.
This is all well and good but it needs something to it: a universal mythos must be universal.
There are common themes amongst mythologies, and this is something that is used in the story by the actual travel of the Queen of Sheba, post-Solomon. Her story is fascinating as her trek takes her across two of the most major sets of mythological structures in mankind, and arguably across all of them. If the Tiamat story is used as the template for other mythological starts, and then broken down into some salient parts with differing emphasis, nearly all of mankind's myth cycles are coincident with it via the types of characters within it.
Dragons, of course, as Tiamat is the Mother of Dragons, play a part in Genesis (the Serpent) and in nearly every other mythos cycle on the planet. They are the Naga in India, as Dragons in various forms in SE Asia, China, Central Asia and into the Americas (derived in part from Asiatic groups) and into the Scandinavian mythologies. In traversing across the lands to seek out the beginning of the Hebraic Tradition, Sheba crosses parts of multiple mythos groups until she crosses into China and finds a related group with very different sets of emphasis. Between those two points, roughly from Babylon to the eastern Chinese coast, is a line and somewhere along it that is narrowed down to the mountains and passes of western China must be the start of all myths. It is to there she heads back and is transformed into a Goddess... or just transfigured as the case may be, stories vary. She is, however, the Queen of the West and she makes a final home for herself not in the lovely cosmopolitan environs of the larger cities of China, but out closer to the hinterland, closer to that point between rural Chinese mythos and the Hebraic tradition.
If you have to have a creation mythos start anywhere, that is as good a place as any, and later traditions would transform that mythos via locale and shift out names and even physical entities, while keeping actions much the same. From that point on a world very similar to ours, but with differences imbued into it, begins to take shape as it is one that has multiple possibilities in it, and a wide swath of beings, plus powers that then have their own definitions within the larger context.
I leave major questions unanswered, like - What happened to the Tablets of Destiny? Did they exist? Did Tiamat let others look at them or have them? Did she make a copy that left major discrepancies in place to work out future eventualities? Was death her destiny, or was it something else? And just what were half the Gods and some of the Monsters doing, anyway? And if she is reborn from the dead body she once inhabited, what would that mean to the inhabitants of that universe, as it would be a rebirth of more than just physical nature (although it starts there)? They don't need answering as the story doesn't, in the end, provide a means to get them answered. What the story does provide is a perspective that goes far beyond the human perspective and yet is amenable to understanding and even confronting.
To do that means taking actions while not knowing everything is an act of both desperation and courage, and each character must bring themselves to reconcile who they are with what they know and put it all on the line. Victory is never complete, never fully consummated and the price for it can be high... and yet far worse is defeat. The reader gets the wider context of all the lives involved, and yet even the reader doesn't and can't know everything, but can see people with much less information have to work with it or have it work on them. That is how the various types of myths work and while we don't think of ourselves as people of note, it is only the far distant future that will decide what was a great deed and what was just pure luck.
* * *
The physical structure of Gotham City makes it not just a place to tell stories, but one in which the structure very much influences the stories that happen there. This story gives a massive increase to the actual physical outlay of Gotham City starting from the ground and going up. This is not a place of merely flat islands with a river bisecting it, but now partakes of the physical geography of the region. To do this the actual description of the islands as seen with their modern overlay presents a place that has hills to the south and west, plus steep banked bisecting river, and some minor hills around a minor depression in the east central part of the North Island.
Both islands participate in the slow uplift of the crust after the overburden of the ice sheet during the last glacial period was removed. This goes at about an one-half to one inch per year (more in some places, less in others) and slowly changes the way that Gotham looks over time. The somewhat swampy, mosquito infested semi-islands with some higher hills to the south west then leads to the slow drying of that land into forest and scrub land, and then it can be cleared for cropland. From that the Gotham River tends to go a bit faster and cuts a somewhat steeper channel as it does so, while following the glacially enlarged channel of the river that preexisted it. This was a boon to early water-driven factories and allowed for the early industrial era to thrive in Gotham City and become a real city.
What this also does is start to raise the bottom of the old harbors and which then silt up faster than they would in a static environment. No matter which way the current goes around Long Island Sound, there will always be silt and sand from the Gotham River moving with it to be deposited on the bottom of those areas with slower water flow compared to the river. The Marina on the North Island is a major beneficiary of the river as its current tends to carry sediments beyond the Marina and the tidal mixing ensures that it can never really stay there. To the west on the northern part of the South Island, there is some faster deposition, which builds up its outlet to a degree, although that tends to be washed out during major storm events. The central channel carries the least sediment, but has the greatest impact on the harbor front, as the current spreads out and deposits sediment readily on the sloping sub-surface. Taken together silting and uplift change the structure of the harbor and its navigability, so much so that when it is not maintained out a bit further into the Sound, deep water traffic can no longer safely navigate to Gotham City. New York City has the mighty Hudson, and that has become channelized not so much by uplift but by out fill into the current. Both of these cities have seen the disappearance of swamps and bogs through much the same process of uplift, outflow, infill and back fill so much so that you can't see what the original surface of either city looks like.
These are things that need to be accounted for when going through the underground areas of Gotham City, so that a generally realistic and plausible understanding can be given via the descriptions of it. This becomes not a Gotham City of any of the movies, nor is it exactly presented in any of the comics, but a place that is amongst hills, has a river running through it, is two islands, and has a physical heritage that makes it unlike other cities. Yet it must still have some of the things in the canon: a hilly area that allows one to overlook part of the city, a generally flat interior portion that has main thoroughfares, alleys, and twisting side streets forming their own little mini-towns within the city, it has a harbor front and riverfront, an enclave away from the city for the rich, and a diverse culture that is both cosmopolitan and a throw-back to an era when relatively narrow streets made for decent neighborhoods.
Under all of the surface areas, resides those things relegated to the past via the urban renewal period as it happened in Gotham. Unlike other cities that attempted to break up racial enclaves, Gotham City actually used the funds to try and get a better street pattern and surface drainage system so that some of the lowland areas wouldn't flood so readily. Beneath that is the old subway system, plus oldest parts of the storm and drainage sewers. By the time of the story, those things had been built at least 50 years ago (thus 25-50" lower than they are today) with an eye towards finding ways to keep Gotham dry. Now during the worst of storms, the water gets moved rapidly into the Underworld and then into that final set of drains that begin a simple pressure feed via narrowing of drainage pipes towards outlets. At one time those outlets were wholly under water, but now they are close enough to the surface so that their flow can be observed during the worst of storms. The sanitation and clean water systems both had major overhauls during the urban renewal era, and they both function well even if the old water tunnels do need some major repairs. The other thing that also went on was the final shift into the sub-surface of electricity, telephone and other cabling which makes them easier to work on and less susceptible to accidental damage.
Other cities around the world have some similar types of older underground system that was just built over: Boston, Chicago, San Francisco, Seattle, Istanbul and Rome all come to mind. Gotham may have started doing this sort of thing with simply building on top of older structures back in the late 19th century and then made-do through to the post-War era, where it was thought a modern city system would garner modern trade and industries. To that point in time, Gotham had been on a slow downhill slide since the post-Civil War era which was the last hurrah! of railroad locomotives being built in the Northeast.
By the inter-war era Gotham had hoped that a fledgling aircraft industry or new electronics industry would begin to replace the ageing metal working plants and other large scale industrial facilities, but that was not to be with the onset of the Great Depression. After the war the old and dying facilities would leave their marks in and around Gotham City with plants either abandoned or sold off for salvage being the norm. Railways were streamlined and reduced until the passenger part disappeared completely just after the urban renewal period. By then much that had come before inside the city proper was being torn down and built over to disappear into the foundations of the new system on top of the old, and the landscape across the river that used to have major employers now became industrial wastelands.
What that did was clean up the Gotham River, especially the branch to the north of the South Island. Once the new sewage processing plant went in some of the older problems returned, but only for the few facilities on the land side that were downstream of it, and those in Gotham City were in the commercial and warehousing district which had utilized the relatively level areas north of the hills to keep some low draft docks going. By the time of the story the Mid-Gotham River branch has cleaned up almost completely and is one of the more pleasant places to spend an afternoon if you don't mind some of the overgrown rail bed on the South Island side. A physical make-up of any locale will determine what gets put in where, and why, not only for things like docks and buildings, but also for recreation. With that said, for all the waterfront of Gotham City, the actual beaches are on the land side where industries didn't go, usually a bit further up the coast in CT.
The features that made Gotham into an early industrial center were its rivers and docks, with clean and fast running water offering a means for many industries to rise up either through the use of river power or through the water itself to quench metals or be purified for chemicals that would be sent around the world. The very limited space and high cost of being in and around Gotham meant that industries could not expand and that the cost of moving things by freight went up as the rail lines shifted north, and the harbors slowly lost their depth and limited cargo vessels to only the smaller, low draft kind. Much could have been done to ameliorate these things but, in the end, close confines, hills and unreliable harbors turned Gotham City into a place where industries left, not one where they flocked to.
In many ways, great and small, the story of the people of Gotham who live there is one that is based on the very location it is in, and that must also be told in the stories as well. Geography and geomorphology both have roles to play in how the physical structure of a given part of the Earth is viewed (or not viewed when it is under water) and those things influence where events happen and how people view the physical structure of the land when they do things. New York City, as an example, had many streams, marshland and a higher uplands with a river that flowed into the sea on either side of it. Water has been a main limiting point for NYC and it has three water systems running into dating from the Antebellum era, then the post-Civil War era and finally the major water system put in during the 1930's, and it has yet another system being put in place to get water from far upstate NY. Each of those previous systems still deliver water to the city, although not in great quantities which is their problem, and serve mostly as historical artifacts or for filling up smaller pools and ponds. The salinity due to tidal mixing of the Lower Hudson River branches meant that it couldn't be used as a real source of fresh water, thus aqueducts to other rivers were built to give NYC water for population expansion.
For its early life Gotham City could use the Gotham River which only had interacting with the sea mostly on its North Island branch. Like other mill towns in the Northeastern US, it would thrive on water delivered to it naturally. This began to limit its growth in the Antebellum and required a second source of water for the City that would be separate from the Gotham River. I've made, I think, a passing mention to one or two dried up riverbeds and they are dry because their sources were diverted into a man-made reservoir that has an underground aqueduct to Gotham City. Because of the size of the Gotham Islands and useable inland space, this served along with rural well water, for most of the population in and around the city. By the time Gotham City could ever think about having some expansion of its industrial base, most of that industry was moving westward and out of the Northeast section of the US and the last real boom time for Gotham City was the 1920's and the decision was to concentrate on electrification and subways and less on infrastructure to allow further expansion of the City.
The last glacial period deposited a lot of material at its terminal moraine, which is to say the furthest extent of a glacier and the line which materials in the ice get deposited by the movement of the ice within the glacier. All of Long Island is terminal moraine material, as an example, and is a temporary phenomena that only has lasting power due to the sheer bulk of the material deposited there. Gotham City has actual bedrock underneath what was deposited on it by the ice sheet, and while the general terrain is still represented, it is with the overburden masking it. This presents an interesting case because rainwater going through such overburden is naturally filtered, and while the quantities are tiny, they do appear throughout the region and it would be expected that the South Gotham Hills would also have one or two of these that are more or less perennial due to water vapor being deposited by fogs and mists. These would also be a feature with the land side ridge line, and that serves as a point in the story.
This list can go on and on, from the probable lateral fault line near the Gotham River to the submerged plains out beyond the Gotham waterfront: all of this plays a part in the story.
* * *
To build a reliable story platform requires structuring an environment and characters that have continuity within that environment. This is a most difficult thing to do as it means that prior descriptions of environments and people must hold over time unless they are the subject of the story and change due to the events in or just before the story, itself. In a universal structure of quantum uncertainty this means that once a universe frames et is determined, events that happen off of it must remain in place as background and there is no traveling back to change them as that just gets you another universe. A thread of continuity for future events will hinge not just on such uncertainty but on the outcomes of decisions which finally coalesce uncertainty into a reality. For a fictional setting this requires that the prior decisions and outcomes made in them be affirmed and supported when new stories are written in that universe thread. Once a decision is made, you live with it for good or ill, and that then puts constraints on future events, characters and outcomes. Indeterminacy still holds for the future which is based on a decided past and that thread, once made, is its own thing and cannot be anything but the basis for an alternate history if you want to change it. At best it will have similar settings and characters, but with a different background to it if it is to be revisited to get different results and those changes in the past to get this new thread must be delineated for the reader, as well.
Writing a first alt-history for a fictional setting that was a blending of two universes (at minimum) meant having to determine just what was different and why from the two standards being used. The Terminator set of Universes, and there are at least a half-dozen if not more, all have some common basis for their beginnings and each alternate is jumping off from that similar base. To ensure quantum indeterminacy the base, itself, must no longer provide the jumping off point to a given future and, indeed, the setting must preclude anything that can lead to that jumping off point. Those series of events and outcomes and anything like the time frames that provided the backwards time shift means that anyone with knowledge of that future will have their certainty voided. Indeterminacy must hold for quantum mechanics to work, and there is nothing in current physics to indicate that indeterminacy does not hold in all temporal directions.
This is much, much messier than the 'multi-universe' concept as there is no single set of standard multiple universes, and every possible outcome, including universes that have no life, no energy, indeed nothing in them, must also be available. Universes without time are static and in perfect order, a single frame only as they cannot change, although once the possibility for change arises, they then begin to create the wide plethora of possible outcomes from that possibility of change. It can be proposed that almost all of the universe types available have little matter, little energy, little light, no life and are quite dull places as that would be the norm for very low energy events. They would have different physical laws, different standards and this vast majority of universes would not only be uninhabited but uninhabitable. In turn, due to the low rates of change and the low possibility for change, from their starting null frame these universes generate very few frames due to the low amounts of material and probable outcomes for them. By type the vast majority of universes you can get to are of little to no interest beyond theory.
Thus while the very first few frames of all universes have little in them, it is the few that have a lot of energy in them that then generate up the most number of variant frames as they have a lot of possible outcomes. Once there is any basis for making decisions, which starts at single cell life forms within our set of laws for life, these universes then proliferate further as decisions and events change outcomes. Thus while the most number of universe types are those with little in them, the greatest number of universal frames comes from those few that have a lot going on in them. Because of the near infinite variations that these decision dependent universes create they will overpopulate the frames of all universes that are available as those with little happening don't do much in the way of frame generation. Billions of years, which is a nearly unquantifiable number of frame possibilities later, the general soup of all universe frames are those with life, even though they may be in a slim minority by type.
Once a decision for a frame and thread are chosen, then the indeterminate becomes determined and set for that thread association of features. The Terminator Universes are relatively staid, no matter how they come out for brutality, their starting point is one with a high similarity to the actual world if very advanced in technology at a given time frame compared to our reality. Their universes shifted from ours not with CyberDyne but with the events prior to the technology it created, which places that at least some decades before it. The World War II of that set of frames may have been slightly more advanced and lasted a few years longer with a greater death toll to it due to jet fighters, rockets and nuclear devices. That would yield up a chillier Cold War that would then build on those immediate advances towards a more complex computing structure needed to back those military platforms (and their civilian counterparts post-war). That yields a CyberDyne and Terminators, while our reality of threaded frames does not. That reality is a close cousin to ours, but not exactly ours, either.
On the other side, the Batman side, there are a number of variant timelines to choose from, and nearly every change in artist and writer groups for the comics yields an alternative setting for the characters. The TV programs, movies and other items like standalone graphic novels yields up a still further number of Batman variant universes which all have some number of similarities to them based on character and a few specifics about Gotham City. With that said only the recent movies give any glimpse of what Gotham City is actually like, starting in the 1980's and then goes a bit off the rails until it is re-booted with the most recent features. Getting a coherent Gotham City is necessary for any writer, and while those who came before were given large creative leeway (indeed, unmooring Gotham City from ANY locale) that cannot do for a longer written piece that is attempting to put a portrayal of the people who are a part of the story into perspective.
Taken together the more advanced technology series of the Terminator Universes must join with the Batman canon at a place of intersection that draws on the backgrounds of both, but is not, exactly, like either of them. Once the story is put into a setting that is Gotham City the elements from Batman will predominate, but they are now tempered by some major parts of the Terminator Universes as there must be some quantum basis for those Universes to exist for the target time frame to be a valid destination that is, at the same time, a variant of it. That yields the necessity for a more standard World War II, presented ably in the DC Universe, and have it be one with just a few hints of advancement beyond what we see in the war itself. Those few advances, however, follow in a wake of time more along our reality thread, and that garners a number of items to help shape the reality that the first story takes place in.
By setting Gotham City into the Northeastern US it then gains the historical trends and background of that region. Much of New England has that air of deeper mystery to it, an aura of age and the embodiment of natural life that allowed for something that was not, exactly, witchcraft nor mysticism, which comes with that landscape. H.P. Lovecraft's writings captures much of that and it is not surprising that the early creators of the Batman material would be influenced by that type of writing. The latter era of the pulp magazines featured much in the way of grand verbal flourishes necessary to pad stories due to the low per word pay rate and they are available preceding Batman being formed as a comic. Even the better written stories of that pre-1930's era read like a deep descriptive narrative of wherever the story takes place, be it a western ranch, a WWI aerodrome, an expedition to Egypt or the high life amongst the well known people in large cities as seen from a detective's point of view. The early comics had to condense that with visual cues and some verbal backing, and that leads to a background in which elements of H.P. Lovecraft can naturally appear and flourish. Batman was not written in a vacuum and is influenced by the types of stories known for the era it started in.
Luckily there is no, single, Lovecraft thread or universe, but a plethora of them based on the Open Framework scheme of those works. By allowing the schema of the Cthulhu Mythos to be re-purposed, it has spread amongst many writers over time so that you can find Stephen King, Robert Bloch and Ray Bradbury all using elements of the Mythos directly or indirectly in their writings. Yet it is a Mythos meant more for horror and mystery writing than science fiction, and in my writings I have done my best to adhere to science and science fiction as the concepts for my writings. This does not exclude the Cthulhu Mythos, but requires an understanding of just how it applies in a more rigorous framework that is science based and derived.
The Gotham City I present is the natural blending of setting necessary to do this as it draws on the mystical nature of New England, the early and mid industrial revolutions, the slow decline of Gotham as a manufacturing center, and all the other elements that a city of its type in that place would have over time. In this Gotham City the Cthulhu Mythos blends in and with relative ease because it IS so close to 'Lovecraft Country'. That proximity was something that helped to craft the first story, and to put in the necessary undercurrents to let the reader know that this wasn't just another Gotham City, but one that was its own place and distinctly different by being put in an exacting place.
Gotham has always been the place of Gargoyles and Gothic buildings done in modern ways, and in this place it now gains something of a haunted undercurrent to it. That undercurrent is not the main current, by any stretch of the imagination, but is always present and can often arise at odd times. Those who try to live too close to that learn that it is not really a human aspect of the city, it isn't just normal ghosts that exist (although that would be expected to a degree) but one that has the ever present hint of horror to it. No matter how hardened the criminal, if they stay too long in those places they will find it not to their liking and while they may not admit of fear, they will just say that 'you really don't want to do anything down there' and leave it at that. Yes if you must escape, use the Underworld, but know that a prison cell may be a better fate than what you are going to find in the forgotten realms of Gotham City.
The Batman is a part of that, the dark avenging inhabitant who becomes a shadow manifestation of the deeper darkness under the City. Because of his purpose and persona, the man who is Batman is in some very special way, accepted by Gotham City because of his mission. If there is horror there is also the acknowledgment of avenging it, and going into a dark realm of the soul where the confrontation isn't so much that of fists and guns, but of the darkness clouding the soul is one that fits well with the setting. Random horror was visited upon Bruce Wayne, and now his purpose has taken that horror and remolded it to his own ends. In a very real way that is part of what Gotham City is and by doing that he is accepted by the City. Bruce Wayne's first real encounter with a Ghost Train was in this story, not just some fleeting motion or sound, but a very real encounter at close range which was something relatively novel for him. Yet it does not shock him and his scientific mind does not reject something that can manifest, has physical parameters and can then disappear like that. He already has that framework delivered earlier in the story and he now has seen it in action: it is just another factor in the grand equation of Gotham City to him, relatively random and yet it is there.
Elements of continuity include not just setting and characters, but the events that are ongoing due to other events not in the story. Thus there are continuity ties that looks at criminals going to trial, local lore and stories, plus the fallout of events from the first story.