Complete Set of Region Maps
The Cathedral Galaxy setting is now complete with a full set of regional maps, each highlighting a particular area of the galaxy and an aspect of the setting. Extra lore and artwork are scattered throughout, in addition to the larger overview map and establishing descriptions of each region posted here. Enjoy!
My next step is writing a story in this galaxy. I will not make any statements on how long that will take!
In addition, I’ve had a few people ask me about setting role-playing games in the Cathedral Galaxy. That idea intrigues me, and I’m happy to learn that players are interested in using my universe for their games. So, I have put together some lore and gameplay reference materials that you may use. Click through to read more.
Game Master References
The Cathedral Galaxy is a distant sci-fi setting where advanced galaxy-spanning civilizations live among thousands of artifacts and ruins from an ancient precursor civilization.
- 15 Jan 2022: initial
Credit and Approved Use
The Cathedral Galaxy maps, the material on this web site, the short stories “Conference,” “Between Wrecks,” and “In the Arena,” and the setting itself were created by Joseph Shoer and are shared here for private use under the Creative Commons (BY-NC-ND: attribution, no commercial use, no derivatives) license. Attribute as: “The Cathedral Galaxy created by Joseph Shoer, http://josephshoer.com/cathedral”
These resources exist because I have been asked about tabletop RPG adventures in the Cathedral Galaxy, and want to provide background material that will better define the setting and be compatible with my own future works. They are provided here for private use for free. You may create your own characters and situations in this setting for the purpose of your private tabletop games. (If you do use the Cathedral Galaxy for your campaigns, I am interested to know about it – and curious how your adventure turns out!) For all other uses, contact me at firstname.lastname@example.org.
I acknowledge many influences from the last several decades of science fiction, including but not limited to Banks’ Culture series, the Homeworld games, the Star Control games, Star Wars, Tiptree’s Starry Rift, Asimov’s Foundation, Chambers’ Long Way to a Small Angry Planet, and Corey’s The Expanse, and probably others that I’m not thinking of at the moment.
Travel between star systems in the galaxy is feasible and common, but troublesome enough to require an investment and some advance planning.
The easiest method of travel is through a network of artificial wormholes left by the vanished Ancients. The network has various names: Channels, Arteries, Conduits, etc. The wormholes are sustained by gargantuan space stations, still functioning after millennia in operation. Unlike many SF depictions of wormholes, they are not rings; instead, the Anchor stations are spherical with open lattices in various shapes. (If you read the short story “Conference,” an early description of the wormhole gate station does refer to a ring. This will be corrected in future works.) The wormhole itself is spherical (as depicted in the movie Interstellar) and located in the center of the station. Ships fly through the openings in the lattice, proceed into the wormhole, and appear on the other side where they must exit through the openings in the station of that gate. See the artwork on the map of The Traders’ Rim for an example of a wormhole gate station.
Each wormhole pair connects exactly two locations. The points on the map which have multiple wormhole paths converging on the same location actually represent multiple anchor stations in the same star system. They often orbit one another, but sometimes are spread apart in different locations in a star system. Because being near a wormhole anchor means immediate access to information, trade goods, and travel from across the wormhole network, planets near gates become economically prominent and major space stations crop up near the anchors or in the anchor systems. Many anchors are named for features of the astronomical landscape near them, or the planets and star systems they reside in. Travel through wormhole gates is generally free and open, with traffic coordinated by local authorities on each side. (Transmission beams pass through the wormholes.) An exception is the Free Worlds, in which the controlling powers of each gate might charge tolls, impose restrictions, and so forth.
It is possible to destroy or deactivate an anchor station, and this has happened in the past (see the note on Babylon in the Exiles map), but that would be a major galactic incident. Non-functional wormhole gate stations are scattered through the Galaxy, indicating that the network was once much larger than it is now.
The second means of interstellar travel is called “spatial trajection,” and it allows a ship to instantaneously – in its reference frame – jump to a point within a range of its starting location. A trajector jump carries a relativistic consequence: while occupants of the ship perceive the jump to be instantaneous, to anyone outside the ship an interval of about 26 days will have passed. This interval is always the same regardless of any characteristics of the jump.
The energy class of a trajector in units of teraquark-volts (TqV) governs how far a single jump will carry a ship. The largest ships can mount the longest-range trajectors, though there are some specialized courier vessels consisting of a small spacecraft proper mounted to a huge trajector and power plant. There is a diminishing return as trajectors get more powerful, as indicated by the decreasing range interval on the jump scale of each map. The key indicates the ranges of trajectors that might be available to regular spacefarers (traders, scouts, pirates, etc.); some governments, militaries, syndicates, or extremely wealthy individuals might have access to higher-range units. Trajectors take some time and energy/fuel to recharge after a jump before the next jump can execute. The interval varies depending on the ship, but is long enough for an encounter to take place and short enough for a ship caught between intermediate jumps to feasibly escape from attackers by evading them long enough to recharge.
Communications between star systems takes place via trajector drones that carry broadcast packets in a series of jumps toward/away from the nearest Anchor station. Once at the Anchor, information can be transmitted directly through the wormhole. Essentially, information transmits instantly through wormholes but then propagates out (or in) from the gate stations at the same rate as a ship trajecting.
The 26 day time discontinuity associated with jumps may not matter to players if their party stays together. During a jump is a good time to introduce events that occurred “off camera” — keeping in mind that information also travels through the galaxy via trajector jumps, on courier drones. It takes about 390 days or less for a message drone to reach most of the galaxy from the nearest wormhole artery, but as much as 520 days to reach the most remote parts. If the party splits up, any characters who don’t take part in a jump will have about a month of activity to account for. Be careful of accruing large age differences, as it may take several jumps to get where the party is going. This map showing the time elapsed during sets of 5 jumps from each wormhole gate may be helpful in figuring travel times and how long it takes for information to get from place to place:
It is simply not feasible to travel into the Cathedral core. The radiation there is too intense, as indicated by a boundary on the Republic map.
Spaceships and Stations
Gravitic compensators have been discovered in the ruins of the Ancients, providing the people of the galaxy with a technology for artificial gravity. However, it is generally large, energy-intensive, and expensive. Therefore, most smaller ships should be laid out as if thrust or centrifugal force are their only sources of gravity. Only the largest starships, and usually only large space stations, would be laid out on any kind of a deck plan that requires artificial gravity. Another technology based on ancient relics is the inertial drive, allowing ships to engage in large delta-velocity maneuvers (including launch and landing) without carrying huge tanks full of propellant mass. Populous worlds would commonly have one or several space elevators to facilitate ship traffic.
Most sensors, weapons, and devices should conform to some recognizable principles of physics. However, higher energies, larger scales, and more precise manipulations than we have in our world today are available as general technology. A small number of exotic “indistinguishable from magic”-type technologies (such as the gravitic compensators and inertial drives already discussed) can be derived from the ancient artifacts, but remember that the Ancients generally had to build star-enclosing spheres and planet-scale focusing mechanisms to do that sort of thing, so if you want an exotic effect to occur, it is best to have it happen at such a construct.
Many of the largest space stations are repurposed ruins or relics of the Ancients, especially anything constructed to be moon-sized or larger. For example, the Colosseum and Harbor are both Dyson-sphere-like enclosures of their host stars. The new occupants take over empty spaces and sometimes cut into or modify the structure to create the rooms and spaces they want.
For artistic inspiration for space structures and ships in this setting, I look at Chris Foss, John Harris, and especially John Berkey artwork. Harris’ is more closely aligned to the ancient artifacts than to contemporary structures built by active galactic civilizations.
Artifacts, Constructs, and Wrecks
Artifacts and ruins of an ancient, vanished starfaring civilization are scattered throughout the galaxy, both in space and on planet surfaces. They date back at least fifty thousand years before the present time, or perhaps as much as a hundred thousand years. Some of them still have unknown functions after all this time. The most awe-inspiring constructs are bigger than moons or planets, or even surround and enclose stars. These are so large that their structures should not be able to support themselves against the force of their own gravity, which would pull them into collapsed spheres, meaning that some kind of control or active field prevents collapse. This technology is not presently reproducible. Conversely, in artifacts where the support field failed, they have broken apart and collapsed (as in the Burial Grounds).
Archeological study of functional artifacts is a major source of technological advancement in the galaxy. The Great Library at Museion in Shobah is an authoritative collection of information gleaned from the ancient constructs — though not the only one. The Republic Institute at Yama and the Great Fields Observatory are also important institutions.
Scavenging wrecks and ruins is also a prominent activity in the galaxy, yielding new information, technology, or raw materials. The gate at Isis is a popular jumping-off point into the Burial Grounds, and traders specializing in salvaged material concentrate on stations there.
There are both functional artifacts and broken wrecks in every region of the galaxy. Only major ones are indicated on the map. The space between inhabited planets is wide enough that even a traveler in the populous Republic or Imperium might discover a new minor artifact.
Many constructs have been repurposed as space stations by present civilizations. For example, the seat of regional governance in the Halls of Taron is Taron’s Throne, a large flat planar construct that has been made into a grandiose capital facility. The present civilizations of the galaxy cannot build structures on the scale of the Ancients, so any station bigger than a moon or planet must be a repurposed ruin.
Peoples of the Galaxy
There are no humans in the galaxy. As on the maps, the term “people” should be used instead of “species” or “race.” Instead of “intelligent people” or “advanced people,” use “starfaring people,” as new peoples may be evolving but not yet known. Instead of “alien,” use the term “creature,” and remember that these peoples have been starfaring for thousands of years, so in order for a technology or ship to appear so exotic as to deserve the term “alien,” it has to be really strange to everybody in the galaxy.
I have not detailed the characteristics of each people in the galaxy, partly by intention. There should be a wide variety of body plans, internal organ systems, sensory structures, inhabited environments, etc. The Cathedral Galaxy does not adhere to the “funny forehead” trope. Also, it is feasible for members of any people to have any occupation or class. None of the peoples of the galaxy evolved in space, they all evolved on planets. Players or GMs may determine the number of eyes, limbs, etc. and game stats for any of the listed peoples for the purpose of your game. If you prefer not to define your characters’ bodies, simply encourage players to use generic terms and action verbs when describing what they are doing, for example, “I shook her hand” becomes something like “I clasped her limb.”
There are two peoples who do not have homeworlds because their stars died out before the present time. In the Mariner Worlds, the Ebuon, and spread through several other regions, the Waygehn. The Ebuon discovered spatial trajection before their star died and moved entirely to other worlds. The Waygehn, however, did not, and so they sent out a number of sublight ark ships in various directions, containing hibernating Waygehn and supplies. Independent arks and repurposed stations join their local galactic community individually.
Each people has 30 to 40 systems containing settled planets and populated stations to their name. They may be spread out across wide-ranging star systems, but would be most concentrated on habitable worlds near the wormhole network. Many worlds, especially ones near the gates, are pluralistic societies with a mix of peoples.
Players should have ready access to translation services/devices if they do not speak a local language. Like in the Star Wars universe, conversations may take place in multiple languages but this should not faze anybody.
The peoples most likely to act on various prejudices are those of the Imperium, Babylon, and the Free Worlds.
Most systems of commerce, information, law, and so on are local to a particular star system. National governments set standards and guidelines, and negotiate with neighboring nations. Local systems use regular courier drones to synchronize with the wider community. Passenger and cargo transport between systems is common. Likewise, religions and philosophies tend to be local and come in many varieties, with the exception of the enforced theocracy of Babylon.
Here is the full list of starfaring peoples in the galaxy:
- In Amseile
- In Harrow’s Core
- Harrow’s Seeds
- Harrow’s Sculptors
- In Babylon
- In The Free Worlds
- Vosh Gatin
- In The Imperium of the Triumvirate
- In The Mariner Worlds
- In The Axiom Republic
- The Artificers
- Anan Keshat
- The Cultivators
- The Fabricators
- In Shobah
- In The Traders’ Rim
- Rogr Valas
- In The Far Reaches
- In The Ramparts
- In several regions
- The Waygehn
The rules, regulations, cultural mores, and presence of sentient AIs vary from place to place. Some peoples shun them, some afford them full rights of citizenship, and everything in between. In general they should be considered as part of the culture they originated in. There are no peoples that consist entirely of AIs, there are no AI “homeworlds,” and there are no general galactic norms governing AIs.
Politics and Culture
Amseile is a federation of smaller kingdoms/empires. It is united under a council of rulers. The various kingdoms warred with each other in the distant past. The war with Shobah was the driving factor in uniting them.
Harrow’s Core is a mysterious place. The native people here (including some outsiders who adopted the local ways) have many beliefs considered strange by the rest of the galaxy at large, including that the galaxy is a single giant organism. They aren’t xenophobic exactly, but they are disinterested in outsiders or outside trade and ideas. They will let traffic pass freely through their gates, and don’t exactly discourage visitors from trajecting through their territory, but they aren’t encouraging or welcoming of this activity. There are persistent rumors that an Ancient weapon gives the people of Harrow’s Core an immediately ability to retaliate in self-defense, fueled in part by the Imperium’s inability to conquer the Core during its expansionary era, but this has never been confirmed.
Babylon is a theocracy with a ruling caste of priests. They devise elaborate rituals and symbols that permeate all aspects of Babylonian culture.
The Free Worlds are a loose association of individualistic worlds that xenophobically resist all outside influences. They see each other as like-minded that band together only out of a shared self-interest. There is no overall government structure; each world conducts its affairs individually and any coordinated action (such as defending against Babylonian incursion) occurs through multilateral negotiation.
The Imperium of the Triumvirate once had a single Imperator, but after the three Triumvirate governors split power it is an Imperium only in name and shared culture. Each region is essentially a separate nation. The governors meet in a council on a regular schedule (with the Imperator not always included). The intra-Imperium politicking and skirmishes between regions are something of an “open secret,” the ruling classes all blow the issues off as Legion training exercises and politics “as they have always been,” but privately the governors are ruthless in their pursuit of their own ends (Golaj the most so, Aoreu the least, and Erhn is inexperienced).
The Mariner Worlds are characterized by free-spirited, live-and-let-live personalities. They are explorers, wanderers, and artists.
The Axiom Republic is a complexly balanced melting pot of different cultures, with a wide variety of diversity among its peoples. The central government is deliberative, structured to move on good-faith assumptions to represent and respect everyone’s viewpoint. (It is not a satire of parliamentary debate and bureaucracy; it is a functional and working system, that sometimes becomes cumbersome by its deliberativeness rather than dysfunctionality.)
Shobah is a stuffy nation of know-it-alls. The Library is so culturally dominant here that almost it is almost the de facto government and baseline culture. Think of it like a huge old university.
The Traders’ Rim revolves around trade and commerce. The government of this nation is more like a chamber of commerce; its highest priority is preserving the integrity of the Traders’ reputation among all the peoples of the galaxy, recognizing that doing so includes maintaining strong banking institutions, financial regulations, norms of exchange, licensing, contractual obligations, dispute resolution, and so on. Almost every punishment handed down in the Rim for violating its laws would be monetary or economic in nature. This has been successful and the Traders are trusted even in the Free Worlds to be reliable in meeting their obligations.
The Far Reaches is a region with no overall nation or government – the Hrag and Moskavan (and even some of their worlds) are fully independent from one another. The key feature of this region is its emptiness, which breeds some amount of isolation between those two peoples and the rest of the galaxy.
The Ramparts likewise is a not a single nation. Its natural hazards have perhaps encouraged or attracted lawlessness, piracy, and criminal hideouts. This is not to say that the Ukanewish and Pzrrn are all pirates; in fact their homeworlds are relatively safe and well-governed places. Also, members of peoples not native to the Ramparts may move in to join the pirate gangs.
All evidence suggests that starfaring life evolved in the galaxy in two bursts. First, around the year -50k000 or before, a civilization or group of civilizations emerged and built all the artifacts and ruins, including the network of wormhole channels crisscrossing the galaxy and enabling interstellar commerce in the modern era. The Ancients, the Old Ones, the Elders, the Archaics, the Precursors, the Lost, the Forerunners – the peoples of the galaxy have many names for them. They apparently vanished from the entire galaxy sometime around year -20k000 to -15k000. The second burst of life emerged in the galaxy around the year 0, and comprises present civilization.
It is not known to the peoples of the galaxy at the present time, but the Ancients vanished because they discovered a way to achieve immortality of a sort. Their engineering reached galactic scale; they determined that they could create a gargantuan computational engine out of the galaxy itself by integrating their constructs with the physical processes of stellar evolution in the galactic core. The galaxy functions as a giant organism, with the wormhole network acting as a circulatory and conveyor system for material and information and the physical interactions of stars within the galactic core acting as an enormous neural network. With the computational capacity established, the Ancients were able to upload their minds into the system. Their minds now work at slower speeds, and they no longer procreate, but they will last as long as the galactic engine survives. Any remaining Ancients who chose not to upload their minds died out long ago.
The Ancients generally do not concern themselves with galactic affairs, unless it involves maintenance of the galactic system that sustains them. They cannot generally act directly in the physical world, so in those cases, they maintain a set of agents who can act in the galaxy on their behalf, for example, by influencing galactic politics to encourage or discourage more traffic through a particular wormhole gate. The primary agents are members of the ancient civilization sustained in hibernation within secret artifacts until called forth to act. These primary agents sometimes recruit ancillary agents from contemporary civilizations. One of the main hibernation bases for the primary agents is located near the far end of the Necropolis Field, a group of ruins in the Burial Grounds that is thought to be mostly scavenged of most valuable material but is extensive enough that it is not fully charted. Some of the Ancients’ structures and artifacts are designed to maintain communication with their agents; the Spire is one such place with a dedicated communication chamber where the Ancients can speak to their agents.
Player characters will not be able to interact with the Ancients, except potentially through their agents. If a player is an agent, they would only communicate infrequently with the Ancients, such as to receive a mission and report results. This would only occur in person at an artifact, and should take place in secret from any players or NPCs who are members of the galaxy’s current civilizations and peoples. Agents generally should not get explanations of their assignments from the Ancients, just instructions. They may be able to occasionally ask the Ancients for help with something, but the Ancients’ ability to influence the galaxy is mostly limited to turning certain artifact functions on/off. Between missions, agents may act as sleeper members of a current society or resume hibernation. If the Ancient minds need to reach out to an agent, they would send another agent to go get them and either assign a mission or tell them to visit a communication artifact. Agents are their own set of species, not named in the list of peoples above. Other characters would see them as similar to, but not quite like, some other people, i.e. “so-and-so looks like an Amadi, but slightly unusual,” but if you have defined stats for the Amadi the agent player may bend or break those rules (as they are actually not Amadi at all). Players should not be members of the ancient civilization. Players should also generally not discover that an agent is such except in very unusual circumstances; they should remain unaware of the continued existence of the ancient civilization. I am telling that story!
Recent Events and Changes in the Galaxy
Though it has persisted for tens of thousands of years, at this time the Ancients’ sustaining computational system is showing evidence of slow degradation. The most obvious symptom of this degradation is in the behavior of the Revenants (see below), but there are others visible to the new civilizations:
- There is an increase in the number of novae and supernovae in the galactic core.
- Some artifacts and constructs are ceasing to function, changing their behavior, or even coming alive for what appears to be the first time. This sometimes causes problems if, for example, an ancient construct used as a space station suddenly starts generating dangerous levels of radiation.
- Rarely, a wormhole will cease to function or a long-inactive wormhole route will start up again.
Research teams in the current civilizations are only just starting to notice these phenomena. It is still controversial, as depicted in the short story “Conference.”
The Ancients have come to the conclusion that their sustaining computational engine is threatened, but have not yet reached any consensus on a course of action. There are two major factions taking shape within the computer forum: One faction advocates that the solution is homeostasis, and some subtle corrective actions should be taken to improve the computational core’s stability. The other faction advocates that the computational core should be expanded, consuming more of the galaxy’s resources if needed.
There is a growing shift in the attitude of the Ancients towards the current peoples of the galaxy. Until now, they considered it vaguely interesting and irrelevant to them. However, some of the ancient minds now believe that the new civilizations’ use of the wormhole network or other constructs is a negative influence on the stability of their system. These are more likely to be members of the expansion faction than the homeostasis faction. The agents of the Ancients are starting to receive some assignments related to these ideas. If the new civilizations take any actions that have major effects on the wormhole network, artifact functionality, or the computational engine, it may tip the Ancients towards a more active role in the galaxy.
To the other civilizations of the galaxy, the Revenants are an inscrutable and fearsome people. They originate in the Underworlds region of the Exiles, but are seen elsewhere in and around ruins and artifacts. They usually seem to have a particular purpose in mind, and generally do not interact with others – but they respond to interference with immediate, overwhelming force and possess weapons that quickly defeat countermeasures. They clearly possess the ability to communicate with one another, but it has never been deciphered. When they move from place to place, local security does its best to keep everyone out of their way.
In fact, the Revenants are another set of agents of the Ancients. They are an engineered species that was supposed to act as caretakers and maintainers of the artifacts that sustain the galactic computational engine, with their knowledge and imperatives hardwired into their biology. The uploaded ancients intended for the Revenants to be a secret, robust way to keep their machinery going without interacting with the physical galaxy themselves. However, over eons, their programming slowly drifted. They no longer accept all directives from the Ancients or their primary agents, as was intended. They still travel to artifacts and carry out some tasks related to their maintenance, but recently they seem to be adding more tasks to their queue on their own
Revenants make for good mindless drone enemies located around ancient artifacts and ruins. The rule is that they always have a mission or task to complete. It is usually not apparent what that mission is, what it depends on, or when it is finished. They will seem to respond to communication one or two at a time, but it is always incomprehensible. Potentially it will translate into words that player characters understand, but the words will make nonsense sentences. They are not telepathic. An agent of the Ancients may be able to interpret the Revenants’ communications to determine their directives and mission, but is not likely to be able to give them new directives. If interfered with (attacked, but also if something disrupts their mission) they will retaliate indiscriminately. Options for getting around them include avoiding them (which local authorities will always recommend), figuring out what their task is and avoiding interference with that or finding a way to accelerate it, stealthily incapacitating them, or waiting them out. It may be possible to defeat them with an immediate, overwhelming counterattack, but once they get going in combat, escape or help from powerful reinforcements are the only options.
Players should not have Revenant characters. There should not be named NPC Revenants, and their missions should not involve trying to interact with anything but Ancient constructs.
Sources of Conflict
There are no wars between the nations at the present time, but that does not preclude some border conflicts, skirmishes, or other political incidents. A true war would be a terrible thing, given the scale of weaponry possessed by the nations of the galaxy. Amseile and Shobah had a full-on war in the not too distant past, leaving the Well of Ghosts as a devastated no-man’s-land where they killed off most of the native life.
- The Imperium has uneasy relations with its surrounding nations. The governor of Golaj in particular seems to wish for supposed glory days of conquest, when the Imperium ruled over a wide swath of the galaxy.
- The three regions of the Imperium also engage in skirmishes with each other. They are essentially separate nations in a kind of cold war, masked by the trappings of the old empire, with a loose diplomatic exchange set up in the old imperial court located at The Seat.
- Babylon has poor relations with the Free Worlds, fears the Revenants, and occasionally engages in bouts of zealous religious conquest. But its isolation limits its reach.
- The Free Worlds do not like anybody and will fight back against perceived incursions.
- The peoples of the Ramparts and the Far Reaches are the most isolated from the larger galactic community, and might engage in local conflicts with each other or nearby factions.
Piracy and organized criminal activity occurs even in the Axiom Republic, and most other nations as well. The Republic does a better job at discouraging and responding to it than many other nations. Shobah, The Traders’ Rim, and Mariner Worlds are also generally peaceful places to be. Local authorities will respond to distress signals, subject to the limitations of interstellar travel. The worst places for pirate encounters are the Ramparts, followed by the Free Worlds, Burial Grounds, and Far Reaches.
Revenant encounters could happen anywhere there is an ancient wreck or station. The closer to the Underworlds, the more likely this is.
The Axiom Republic government can be a source of bureaucratic hurdles for players. Such obstacles should make sense even if they feel onerous to the players; the government isn’t a problem because it wants to be but because it’s trying to balance a huge number of needs among its people.
- Ixidura Fushei Venfale, middle-aged Orij female, the ceremonial Imperator over the Triumvirate
- Ovath, middle-aged Hybon male, governor of Golaj in the Imperium
- Uozaem, old Nermna male, Governor of Aoreu in the Imperium
- Pgala, young Asht female, Governor of Erhn in the Imperium
- Witara Jumet, old Cvinst female, Vice Curator of the Great Library
Short Story Spoilers/Explanations
Between Wrecks: Kaelin dan Voresli is one of the agents of the Ancients. He bides his time as a scavenger between missions. He is able to understand the Revenants better than most because of his status as an experienced agent. This story is likely to have significant rewrites to be more in line with the material above.
Conference: Ceren Aydomi, a scientist at the Republic Institute, accidentally discovers a change in the wormhole network, with some conduits closing/opening, but meets ridicule when she presents her work. The Librarians especially are resistant to the idea that anything could change. Not quite explicit in the story: Ceren’s interpretation of her data is the correct one.
In the Arena: A fight between gladiators in the Colosseum. The Imperium does something where they take volunteers or prisoners and modify them to survive in space, outfit them with weapons, and have them fight as sentient spacecraft in the arena. The gladiators are further modified so that their thought processes move slowly compared to the speed of an orbit within the ring, so as to make for more exciting fights; most of this story takes place in the gladiator’s perception of time. The Imperium could undo that particular modification in the case that a gladiator leaves the Colosseum.
Nobody in the galaxy refers to it as “the Cathedral Galaxy;” that is the name of the setting, not the name of the galaxy itself. In-world, people would call it “the galaxy.” The name is meant to evoke something constructed, over generations, into a massive and beautiful edifice.
Proper names can be poetic, single names, multiple combined titles, etc. Remember that none of the speech organs pronouncing them are human.
Technobabble in this setting often refers to existing concepts from particle physics or astrophysics, to seem like familiar or attainable concepts, but combined in non-intuitive ways or with reference to huge scales. For example, the “Gravity Prism” in the Sea of Relics. (We know what gravity is, and what a prism is, but how does gravity get split into component wavelengths, whatever that means, in a physical object?)
The dating system in use by most peoples of the galaxy starts with 0 around the time when the first civilizations discovered starflight, and replaces the comma or decimal after the thousands place with a ‘k’. The current year is 27k481, and most people are likely to refer to it as “481.” Only dates do this thing with the ‘k’. The standard day and standard year are approximately the same as what we are used to on Earth.
If you have questions, contact me at email@example.com. I may have additional detail I can add to this guide.