The Zeth homeworld is Gel (pronounced with a hard “g”, like “goat”). It's a muggy planet dominated by swampy lowlands.
About thirty million years ago, a planetary acidification event wiped out all life with an internal or external skeleton. What was left was plants and octopus-like creatures. Without skeletons, life on Gel wasn't very fast, or strong, or tough. There were no claws or teeth, but evolution demands competition. Ambush predators dominated, while prey specialized in deception and mimicry instead of armor and speed. As deception piled on deception, the ability to model the underlying patterns of thought in other animals became a necessary survival trait.
On Earth, empathy occurs via mirror neurons: sections of the brain that fire in the same fashion whether observing another acting or taking an action oneself. The same brain architecture that we use to think is re-used to understand each other's thoughts. This is why laughter is contagious, and seeing someone in pain makes us 'hurt'.
On Gel, the requirements of empathy vastly outstripped such a system. Species that did well had entire sections of their mind fully dedicated to understanding the thought process of animals around them. As a result, 'empathy' on Gel involves fully understanding each other, but not 'feeling' what they feel. Laughter is not contagious.
Then the first Zeth discovered that they could trick other Zeth into doing what they wanted, and a society of sorts was born.
Each individual Zeth has an immense ability to understand and manipulate any number of other individuals of any species. Their direct grasp on interpersonal interaction lets them achieve things through manipulation, promises, and reputation that other species achieve via cooperation. Their unique perspective means that they value negative relationships as highly as positive ones. Or, as one Zeth philosopher once said, “friends are safe; enemies are reliable”.
Zeth society is relatively flat and constantly changing. Large scale social structures don't last -- everything's dominated by something between gangs and tiny feudal kingdoms. They've slowly worked their way up to the iron age (mostly using bog iron), but the larger structures of a civilization are absent. No long roads, no large fortifications, no monuments, no plumbing -- nothing that is intended to last for more than a dozen years. Fundamentally, the Zeth don't see society as a real thing, and so don't invest in it.
(When asked why they invited the Zeth, the Faderan usually claim that the Zeth would have found a way to join the Confluence whether invited or not. The actual answer is simpler: the Zeth aren't organized enough to be capable of the worst evils, and so the Faderan couldn't in good conscience judge them unworthy.)
A Zeth in a ramshakel city, with various goods of dubious providence for sale from a wooden briefcase. I have no idea what the glowy cylinders are, but the bronze computer in the middle is of Caylion make. Water damaged papers are also for sale: maybe blackmail material? Zeth are also known to trade in plausible culpability.
The Zeth symbol is one of the oldest, dating back to the first versions of 'Trade Empires'. That said, it doesn't mean anything. Indeed, the Zeth wouldn't have a symbol for their civilization.
While hyperdrives are alien made, the Zeth have just barely enough industry to cobble together leaking spaceships. They tend to make them out of as many pipes as possible, with an excess of duplicate components. That way there's always spares when things break. (It also helps get their ships up and running again after they ditch them into a nearby asteroid -- a common practice to avoid someone stealing the ship).
Zeth language looks like the laziest, ugliest scribble imaginable.
For most species, their starting cards can be upgraded in two ways (often two technologies). For the Zeth, they can only be upgraded one way. This is partially for balance, and partially because Zeth society doesn't quite exist, and has a hard time improving even with incredible technologies.
The entirety of the Zeth economy, such as it is. It mostly involves the flow of information (knowledge, reputation, and deception). Zeth manipulate each other into getting things done, as opposed to having any higher organization. Chains of manipulation can have far reaching consequences, although an actual society would still be better. The top-right has a picture of a Zeth passing deception (in the form of a piece of paper) to another Zeth. Below, that second Zeth passes copies of that deception to two more Zeth.
Universal Translator can be used to expand the deceptions massively, upgrading to Psychohistorical Deception -- the Zeth are now predicting the long term consequences of their lies and tailoring them accordingly. At the right of the card is a branching time line with one preferred future selected.
With an understanding of alien culture, the Zeth can insert themselves in alien societies, filling in whatever roles the aliens see as taboo (since there's little competition). There's no central authority organizing such “envoys”, but it's certainly easier doing “business” with an alien when there's someone living on their world who understands how to “work” with you. At the upper right is a picture of one such Zeth. At the lower-left is a “gift” box of fruit, slabs, and artillery shells.
Cross Species Ethical Equality opens up whole new vistas of taboos for the Zeth to insert themselves into, and new ways to convince aliens to accept Zeth into their culture. With it, the Zeth Diaspora starts: Zeth flee their homeworld and expand into alien societies en-mass.
There are just so many things the aliens consider “intolerable” to buy and sell. It's as if they've never even heard of “supply and demand”. Lower left is a picture of a Zeth with a wooden suitcase full of illicit goods.
With the flexible manufacturing of Nanotechnology, the Zeth can improve their techniques to become Untraceable Confidence Scams. The picture at the lower right is a Zeth proffering a “business card”.
It's amazing how profitable paying someone to not do their job can be. And how profitable it can be to be paid not to work.... Upper right is some IOU notes -- the Zeth equivalent of currency. At the bottom, a Zeth bribes another, who bribes a third, and so forth.
With the ability to calculate the future via Achronal Analysis, the Zeth can advance to Predictive Agent Insertion. Now they place themselves exactly where they're needed to be to create the largest effects. The bottom picture has changed to include a Zeth literally inserting themselves into the bribery chain.
“Customs” and “borders” are mere recommendations of “governments”, and poor ones at that. We have no need for such lies. The smaller and more valuable the good, the easier it is to smuggle. Picture on the lower left is a map of the hyperspace paths early in the Confluence. Upper-left is a Zeth in a barrel. Because of course they smuggle Zeth. In barrels.
With the advent of Hyperspace Mining, the Zeth manage to improve their understanding of hyperspace to the point that they can begin In-Hyperspace Hijacking: catching ships in transit and stealing their stuff. Bottom right is the full hyperspace map, top right a Zeth built ship designed to enter a hyperspace bubble while it's in motion. Lower-left depicts one such ship slipping into the bubble of a Kjasjavikalimm jump core. (Top left is the Zeth, still in a barrel).
Unlike most species, Zeth store their genome in a single-stranded RNA-like structure. It pleats to partially protect itself, but Genetic Engineering introduces better protection for the exposed bases. At the right is a Zeth cell dividing: the genome is in an unprotected cloud in the middle of the cell, and the cell divides unevenly.
The “DNA” to the right is actually their pleated RNA-like genome. To the top is their three-lobed chromosomes. Bottom-left is a picture of a Zeth.
Ubiquitous Cultural Repository
Gel is a world of lowlands and swamps (and a few cratons and extinct shield volcanoes). Waterways and land intermix. The network the Zeth manage to cobble together is very sparse.
Is the same art for all versions of the card, mixing the written languages of all nine species.
Cross Species Ethical Equality
Zeth “ethics” doesn't concern itself with good and evil. The top depicts a Zeth tentacle giving something and another holding a knife (representing violence, or threat thereof), with an equal sign between them. While no Zeth would consider kindness and cruelty to be the same thing, they are both means to achieve one's goals by influencing other's actions, and as such are “morally” equivalent to the Zeth.
The bottom shows a Zeth at the center of a wide web of influence, something almost all Zeth agree is “good”. Not depicted is the Zeth concept of “hubris”, which I couldn't find a way to illustrate.
Interspecies Medical Exchange
Top shows a Zeth's lungs and trachea (located under their four arms). Lower-left shows the Zeth's two-sectioned brain (the second section handles “empathy”). Lower-right is their single-opening digestive tract. Thankfully, they don't speak through it (instead making wet piping noises from their armpits).
Galactic Telecomm Control
Poly Species Corporations
Lower-left is Gel. Lower-right is a Zeth colony ship: put together just barely well enough to make it to the colony. In practice, Zeth colonize in massive waves of tiny ships, instead of a single huge ship.
Xeno Cultural Exchange
Top left is a Zeth orating on a literal soap-box. Zeth philosophy and oration is highly prized for its ability to manipulate large masses of people simultaneously (It doesn't matter if they believe you, or even if they believe that the rest of the crowd believes you. All you need to convince them is that the rest of the crowd will act as if they believe you, and you give them no choice but to act similarly).
Top right is an arm band, because even the Zeth like jewelry. Bottom right is a branched (armpit) flute. Bottom left is a wanted poster... the closest thing I could find to “high art”.