Designer notes: Like any good fantasy kitchen sink setting, the Inkiverse includes creatures that combine animal and human parts, such as merfolk, satyrs, and centaurs. In most settings, such creatures are just there. The Inkliverse gives an explanation of how these blends came about.
Transformations are creatures that mix human and animal anatomy. They are the result of the animal Oversouls seeking servants, minions, or at least allies. They augment yaoguai. Like yaoguai, they bring the human advantages of abstract thought, speech, and hands. Unlike, yaoguai, they are much less magically powerful, but they are still Stewards, human enough to still be in charge of the Earth, with consequences for issues like animal-themed magic, nymic magic, and exorcism. And the Oversouls and yaoguai consider them more expendable.
Transformations are each made from a human being. They do not propagate by breeding. Each merman, mermaid, centaur, satyr, etc., was once fully human.
The human part of a transformation is made of human tissue and the animal part of animal tissue. The anatomies of the two parts are as true to species as is practical, though modifications and compromises are necessary. The genetics of the animal tissue is as close to the original human genetics as possible for the species in question.
These transformations are always transubstantiations. That is, the new form is now the (ex-)human's true shape, what they now really are—so this is what any disenchantment of later transformations will revert them to, unless that later transformation is another transubstantiation.
Scorpion folk are the oldest class of transformations. They are created by the Arthropod Oversouls. Arthropod yaoguai, known in human folklore as the tiny insectile "bug fairies," maphgia, are quite powerful, but sometimes you just need someone big.
Scorpion folk are made when maphgia approach a human and make the offer to transform (or occasionally transform without asking, but experience has taught them that volunteers work best).
Scorpion folk have, as default form, a centaur-like form, human to the waist, then beyond that the body of a scorpion from the claws back. They are very tall, seven to nine feet, which means very long torsos since the scorpion body is low to the ground.
Native magic allows them to assume human form, though at ten to twelve feet tall, with an optional scorpion tail, but they cannot hold this form past sundown or sunrise, whichever comes next.
Besides being large, they are strong, fast, and tough. (The attitude of the maphgia is that, if you need big help, make big help.) They do not age. Though they do not breed, they come in both sexes. (The two mentioned in the Epic of Gilgamesh are a married couple.)
Each of the scorpion folk was transformed by some specific maphgian, almost always on some specific understanding, e.g. "I turn you into a superpowered, ageless monster (if you like) and you serve me one year out of every six." The maphgia often trade their services to other supernaturals.
Scorpion folk are trained in all forms of combat. They are fully as intelligent as normal humans and may also be scholars, given long lives in which to study. They are not always mages, but they have the capacity to learn magic. Magics common among them include:
Scorpion men have been a success, generally, inspiring other Oversouls and their yaoguai to invent their own transformations.
Designer notes: Scorpion folk are connected to the sun because, in the Epic of Gilgamesh, they guard the sun-god's palace. Those scorpion folk are titanically high and of godlike power, so this version is really toned down.
Merfolk are the most widespread and populous transformation. They are the product of the Fish Oversouls, not the Oversoul of any more specific class of fish. As a result, merfolk vary a great deal in details of appearance—coloration, build, and forms of fins. The fish part of each mer is, in effect, a unique species.
Merfolk have caudal, ventral, anal, and dorsal fins. These are arranged in standard piscine format, so the caudal fin is vertical, not horizontal like a dolphin's or like adapted feet.
Merfolk have both lungs and gills. The gills open near the waist, where the fish part begins. The piscine part is cold-blooded; the human part is warm-blooded, but includes counter-current heat exchange networks under the skin and at the vessels leading to the piscine part to retain heat. They can tolerate either salt or fresh water, though they go through a few days of fatigue adapting from one to another.
Merfolk have lateral lines along their piscine bodies, allowing them to sense pressure and vibration as fish do. They also perceive the electrical environment and sometimes have electrical powers in the manner of electric eels.
The mer transformation is not done by enchantment by a fish yaoguai, the way the scorpion folk transformation is done, but by a magic potion. Yes, the potion was introduced by fish yaoguai, but the recipe is now widely known to mer-mages (sea witches, if you like). See the myth of Glaucus. In his case, the potion was spread on the herbage by some party that wanted him transformed. When any human goes mer, the question is always "Did they dive or were they pushed?"
Merfolk are all able to learn magic, though not all do so. Common magical themes for them are enhanced singing, weather control, sea-life themes, and seemings that let them pass for human and walk on land.
Merfolk are unaging, so they have accumulated to fair numbers, but the bulk of them live in oceanic extradimensional realms. Almost all merfolk wind up in those realms eventually. They may (or may not) hang about the ships or shores of their human lives for a few years or a few generations after transformation, but they almost always move on in the end. The disconnect between lives is just too great.
Designer notes: Satyrs are about the most ineffectual figures in Greek mythology. Even the satyr-god Pan is ineffectual, despite having "panic" named after him. Nonetheless, you do not want one of these hanging out with Lucy by the lamp post. They are figures of degraded virility.
Satyrs were the first attempt to create a mammalian transformation. Several Oversouls worked together, and it cannot be said that this committee effort was a great success. Satyrs are best used as a testbed or a bad example for other mammalian transformations. Hesiod called them "creatures worthless and unfit for work."
Satyrs are invariably male. No one knows why; it was probably a mistake. Anatomically, they are men who have been made more like "normal" mammals, with the following features:
The following features are also present but have not made it into human art:
The goat-legged figures of "fauns" originating in Roman art are actually an artistic convention, with "goat pants" to render the figure more decent.
In addition to the anatomical changes, satyrs have one "superpower": enough endurance and digestive fortitude to get by on browsing leaves in a forest, in most weathers, until the next time someone lets them come to a party.
Why would anyone invite satyrs to a party? Because their psychology, reinforced by tradition and geasa, dictates that, after you get a satyr drunk or high, he Owes You One, and can be readily persuaded or pressured to perform some task for you, or to take some long-term oath of service.
However, satyr psychology also includes ADHD, a tendency to alcoholism and other addictions, and a general gutlessness, so the work you get out of satyrs is not what you could call dedicated. As mentioned, they are not a great success as minions go.
Satyrism is contagious, though only grown men can catch it. Any man who spends enough time with them will, eventually, turn into one. The lure is that hanging about with them for a while causes sexual arousal—the first stages, in fact, of the transformation. The kind of men who choose to become satyrs are generally the kind who have the flaws already mentioned. Many more become satyrs accidentally, hanging about satyr troops too long; they then develop the flaws. It is possible, of course, to keep a man captive with a band of satyrs and induce an involuntary transformation. This is not nearly as common as many a satyr claims.
Satyrs have no more magical aptitude than humans, though mages who become satyrs do not lose any of their powers.
Unlike scorpion folk and merfolk, satyrs age at the normal rate. They are mostly kept as bit-part courtiers by personages like Dionysios or as boy-toys by fay women and other female supernaturals. Sometimes, in realms remote from Earth, male human captives are satyrized as a way to make them docile. If a satyr wants to turn back, get him detoxed and on methylphenidate until he can be transubstantiated.
Designer notes: Centaurs are minor figures in Greek mythology, but they are much more vividly drawn than satyrs. There are five main centaur stories:
The life of Chiron
The tale of Ixion
The Lapith wedding
Pholos and the wine
Nessus and Deianira
Of the five, three involve violence (Lapiths, Pholos, and Nessus) and four involve disordered sex (all but Pholos). And no female centaurs appear in these tales, until late retellings by Roman poets. Probably, centaurs as a class were not supposed to be a race or species, but simply a family, like the Gorgons, the strange and barbaric monster-sons of Centaurus. So, if satyrs are figures of degraded virility, centaurs appear to be figures of disordered virility, screwed-up maleness. But against these figures stands the figure of Chiron, son of Cronos, half-brother of Zeus and the other senior Olympians, mentor of heroes, honorable and blameless. Centaurs have, as it were, two role-models, monstrous thug or heroic scholar-beast.
The centaur transformation was created by the Horse Oversoul, apparently on the strategy of "man + horse":
The centaur transformation is done by being shot with an enchanted arrow. These arrows are produced by centaur mages. All centaurs have the potential to learn magic, though not all do so. Most centaur mages are hippurgists, doing horse-themed magic.
The equine part of the newly created centaur follows the lead of the human part: small men become small centaurs; tall men become tall centaurs; hair color is carried over; degree of maturity is matched; and so on. But there are departures from this rule; for instance, horses can have multiple colors in their coats, and so can centaurs.
The arrow spell only creates a centaur from a man. It usually does nothing to a woman, except wound her normally, but sometimes it creates a fully formed mare, springing from the woman's blood. The mare is as like the woman as possible for a genuine, natural mare. There is no overt psychic tie between them, but neither can bear to be out of sensory contact with the other for more than a handful of minutes, before panic attacks set in. The woman does become capable of learning magic, if she wasn't before.
Centaurs first appeared in the Middle East and eastern Mediterranean. The practice of creating them spread through colleges of horse-mages, changing cultural roles over the ages. Centaurs might be created to be slaves in one culture, warriors in another, adepts in a third. Most of these cultures are far from the prosaic world, but the Cryptic Nation of Grand Normandy has acquired a centaur cavalry in recent generations; see the Cavalry Cycle.
The tetramorph transformation is the most technically advanced transformation, created by the divinitized yaoguai of Africa, the Egyptian animal-gods, as special forces to protect their territories during the reign of the old gods in Europe and western Asia. Every tetramorph combines features of human, cattle, eagle, and lion, but they combine these elements variously. They can even use just a subset (e.g. griffin: only eagle and lion) or just one (e.g. appearing as a simple eagle or human). However, like a fay shapeshifter, every tetramorph has a "true form," a default shape, though these vary considerably.