Changeling Curse

The catalyst of monstrous beastial men and women.

"Ae it tooketh to land, a foul burdenous blight a'mere spear tall, and whence it stood upon its claws it became clear what clothed it was the excrement of man and beast. 'Ere it shouted 'doom upon ye all, for the greatest apocalypse shall drown you!'
I knew'ed then that the Mark of Naduri had cursed the vermin of the sewers with false idolatry and the idiocy of lunatic men. A purge was needed - no, necessary."

— Erwin MacKinley of House Achraveil, on the Changeling Curse.

The Changeling Curse, also known as the Mark of Naduri, is a supernatural phenomenon that curses creatures to sometimes give birth to 'sentient' offspring. Ratfolk are by far the most common example, followed by Arachnae and Fishmen. Although the curse is believed to be hereditary, there are no attributes that suggest obvious carriers. Many carriers are known to either reject their young upon birth, kill them, or raise them as their own; this is often the result of various factors pertaining to the original species' behaviours, such as whether these species are considered 'social'. Gremlin spiders, for example, known for living in social hives, will raise Changeling Arachnae.
Some cultures, such as Cilithorian Elves and Ealden Humans will capture 'marked' animals to breed offspring which they then turn into slaves. Although the practice is considered lawful, many cultures look down upon the practice of changeling slavery (especially in Krezmany, where slavery lead to civil war; see the Wirven Goblin article for further details.)

Symptoms

Birth

The chance of the Changeling Curse affecting offspring depends on its parentage. First generation changelings (with animal parents) have a very low chance of being spawned. Reactions to Changeling offspring vary between species. It is believed there may be thousands of unobserved cases wherein the offspring is killed by the mother.
Second generation changelings are born from two changeling parents, often forming the crux of a new race (Ratfolk, Arachnae, Fishmen, etc.). It is unknown if other species of changelings can breed to form new hybrid species entirely.

Physical Attributes

The Changeling Curse creates offspring with similar appendages to other races. What's most unusual about this trait is that species that otherwise would not have these limbs or, in some cases appendages, such as snakes or fish, have the capacity to be hatched from their eggs with arms and legs.
There are very few differences between a Changeling and the physical attributes of their parent's race otherwise. Ratfolk, for example, still have short fur and teeth like other rats; Fishmen still have scales and fins (with the exception of being born as amphibious and Arachnae still have eight thin legs and a bulbous hindquarters. Many Changelings grow to approximately one or one half metres tall, or slightly larger than their parents (such as Mousefolk).

Emotional Development

Interestingly, Changelings can also develop the ability to express and feel emotions. How this develops varies between species, with some either coming to par with other sentient species such as Humans and Dwarves, simple instinctual ones such as fear or affection, or hardly any like Elves. Changelings retain their species' primal instincts and will often cope with their Changeling form reasonably well.

Life Expectancy

Changelings are not often expected to live very long, given the nature of their birth. Those that survive into 'adulthood' can outlive their parent species by a few years, and even match the life expectancy averages of other races, such as Humans.

Affected Groups

Animals considered non-sentient are the most common carriers of the Changeling Curse. It has been discovered recently, however, that some sentients may, in fact, carry non-active elements of the curse. Elves are argued to be the first and only sentient creatures to carry the curse (as they were once born from lizards).

Hosts & Carriers

Although documentation of the Changeling Curse exists, the research is comparatively smaller than the expected range and scale necessary to create a complete list. So far, it is common knowledge that Gremlin Spiders, Rats, and Fish are known carriers of the Changeling Curse. Other species include Rock Rabbits, Deer, and some species of Reptiles.

Confirmed Changeling Species

Arachnae

Social spiders, such as Gremlin Spiders, are more likely to not only have a carrier within their clusters and colonies, but are also more likely to pass the curse to other spiders due to constant contact. Spider changelings are called 'Arachnae', and retain much of their former species' instincts, such as forming new colonies and hunting for food. As Arachnae are nearly three times the size of their spider parents, they will hunt for larger meals to share with the colony.
Explorers and scholars theorize that Arachnae 'culture' has began to develop, starting with the initial hunter-gatherer phase. Some Arachnae colonies have separated 'areas' within caves to perform certain duties (such as preparing captured food or caring for young) and allowed for other Arachnae to separate to create 'homes' of web where they rest.

Fishmen

A rare instance of the Changeling Curse can be found in river and sea fish. The collective group of Changeling Fish is 'Fishmen' ('-men' being an Ealden suffix for 'type of sentient people'). Many Fishmen become amphibious at birth, and will even take to land to hunt for food considered exotic to fish. Unlike other Changelings, Fishmen will attempt to eat their siblings and parents at a certain age.

Guiren

Guiren are Changeling descendants of turtles, though the most common and normalized among them reside in Tieti and Changaturi. The most commonly seen Guiren are born in Anhao Turtle ('Cipher Stripe Turtle' in most other languages) clutches as they are known to hatch hundreds of dozens every mating season. Much like their parent species, Guiren are often wary of other species while growing up, often acting aggressively toward anything and anyone they might perceive as a threat. Other Guiren, specifically those born in Changaturan cities and villages, are accustomed to both the wilderness and of civilized life. Older Guiren are still wary of other species, but are less likely to strike back when confronted. However, Guiren are also feared for their ability to live for thousands of years, and may even restart their own hearts should they die.
Most Guiren cultures often take a darker ethos to life. A few of their ancestors somehow learned how to wield and harness necromantic powers, the source of which is still unknown. Guiren will join larger cults, where they are taught how to use this power to protect themselves and their people, change the land to make it beneficial to the living, and grant the dead another chance at achieving revenge. Despite the ire this may cause, Guiren are also very respectful of the dead and many living Guiren consider the idea of being raised to help their people a great honour.

Mousefolk

Mousefolk, changeling spawn of mice, are often spared at birth by their parents (unlike rat changelings, see below) for unknown reasons. When they become adolescents, a wanderlust takes over, and they are strongly compelled to venture out into the wilderness. Unlike other changelings, Micefolk are regarded warmly by many Human races, including the Nishati and Irnnen.
Mousefolk culture is often described by other Humans as almost 'gypsy-like', roaming in packs to other cities where they settle and earn money doing odd-jobs for people. The general disposition of Micefolk ranges between warm and neutral; very few Micefolk caravans are considered enemies of the people.

Ratfolk

Rats and Mice are the most common carriers of the Changeling Curse. In Ealdfold cities, Ratfolk are the most common urban threats; many live close to towns and cities (Ealden, Krezmanic, and Casilian cities are known for having dangerous sewage systems for this reason) and will raid them for supplies and food. Rats that give birth to changelings will often try to kill them, believing that they are not theirs. Some rats that have given birth to more than one may realize that they are, in fact, their own spawn.
Surprisingly, Ratfolk have developed an extensive culture, centered around the worship of an entity known as 'The Great Flood', an entity that heralds apocalyptic destruction to the enemies of the Ratfolk. Ratfolk Doomsayers often perform rituals to conjure floods in major cities, spreading sickness and disease as sewers overflow and bring filth to the surface, while Ratfolk Acolytes float with the flood to the surface and 'purge' entire towns in the name of the Flood. 'May the Flood spare you,' is considered high praise and a blessing to Ratfolk allies.

Wolfmen

Wolfmen are a lesser common type of Changeling that attach and bond quickly to groups of potential friends and allies. They are most commonly seen in Ealdfold and Pyychnost, and are mostly considered dangerous predators that lead their pack through villages at night and attack people in their homes. Some in Irnnfold, however, are allied to the Irnnen people, and are considered mercenary wanderers who are called upon by nobility for their hyper-senses.
Wolfmen are usually born to wolves, but some were born to domesticated dogs, typically hunting ones. Changeling offspring of domesticated dogs (or 'muttmen') are sought after by royalty as accessories and staff members to their houses. Muttmen born to stray dogs typically find themselves in the company of other monsters, and will desperately attempt to bond with larger groups for safety. Ogres, for example, love the company of Wolfmen as much as Goblins, and consider them a great addition to their menagerie of pets and allies.
Wolfmen do not often have a culture of their own, but can quickly adapt to life within foreign civilizations. They prefer the company of Humans and Gnomes, as they are much more affectionate and understanding. Dwarves often shun them and consider them vermin, and Elves often go out of their way to harass and torture them.

Epidemiology

It is unknown how creatures naturally inherit the Changeling Curse. However, it is believed that some creatures inherit it by traveling through a Weirding, or by coming into contact with another animal who has been exposed to a Weirding and adopted the Changeling Curse.
When multiple changelings breed, the curse normalizes, causing all future offspring of the parents to be born as Changelings.

Type

Genetic

Origin

Magical

Cycle

Chronic, Congenital

Rarity

Rare