Genetic constructs dating back to the Ekris War, the Echidna Series, also known as the E-Series, was developed in an attempt to harness the innate abilities of the Echidna - a serpentine humanoid species famously known as the "mother of monsters." Designed to be able to breed with virtually any known humanoid species, Echidna series units produce offspring that have pre-set genetic enhancements by default - usually improved constitution, toughened musculature, and heightened kinesthesia and reflexes - and are intended to carry them to term, give birth, and recover from said birth in an incredibly short period of time, with the latest generation able to carry and give birth a typical child of human stock in about a week - and recover and be ready for breeding once more in less than a day. One out of every hundred-or-so births will result in what's called the Nemesis gene; these children will have greatly enhanced physical traits at the cost of inherent mental instability. Due to a flaw in her design, female children of Verlaine Gilneas are always Nemesis carriers; both Crystalliana Gilneas and Valerie Gilneas is a confirmed Nemesis carrier.
Whilst most Echidna-series units are possessed of animal-level intelligence, if that (it was argued by BioLogic staff that intelligence wasn't really all that useful for a creature intended to do little but give birth over and over), there are a rare few unique E-Series units with sentience. Verlaine Gilneas is the most well-known, possessing a series of recessive genes that against all odds, resulted in her having normal human intelligence. The other is Sjathrek, who only possesses sentience due to hundreds of hours of surgery, genetic and chemical enhancement, and augmentative implants.
Echinda units differ dramatically in appearance dependant upon which generation one is looking at. The earliest generations of Echinda Series unit were barely even humanoid, let-alone human-looking, with successive generations causing them to look increasingly human - until generation 6, where they can generally pose as such. All Echidna units are female, and after Generation 3, are extremely shapely and well-endowed. A generalized description of E-series units of each generation follows:
Generation One: The origin generation. E-Series units at this point largely resembled barely-humanoid, man-sized lizards, though with vaguely human facial structure. None are currently known to remain in existence.
Generation Two: Refinements in the process led to these E-series units being a bit more humanoid. Bipedal, Generation Two E-Series units possessed scaled bodies, though they retained largely lizard-like characteristics appearance-wise.
Generation Three: The first "Successful" E-Series unit - as in, the first to be successfully bred in lab tests. Generation Threes are more human-like than previous, being the first generation to possess a body structure analogous to a human female. The first of the series to have more obvious mammalian characteristics, such as breasts and hair.
Generation Four: Generation Four was the first generation developed for mass-production. Improved further, they look even more like humans, though their skin remains yellowish and waxy to the touch due to tiny scales on its surface. Sjathrek is a Generation Four.
Generation Five: Developed for clinical trials and demonstrations, Generation Five E-series units look completely human, save for their slitted eyes (common to all E-Series units), unusual hair and eye coloration, and scaley patches along their arms and legs. #05-04-26 - Red's biological mother - is a Generation Five.
Generation Six: The "Finalized" generation, Generation Six looks completely human barring their slitted pupils and unusual hair/eye coloration. Verlaine is a Generation Six.
Echidna Series units are veritable child-factories. Engineered, specifically, to be cross-breedable with almost any humanoid species, They have a large number of traits designed to assist them in this role. The earliest generations of E-series units had only the ability to breed with most humanoid species; this ability was not entirely implemented and the failure rate of the early units' children was extremely high. Later generations saw countless improvements each generation, including reduced gestation periods, improved fertility, and massively increased offspring viability.
The overpowering majority of E-Series units have a number of easily-identified features. They are genetically compatible with most known humanoid subspecies, are virtually constantly in-heat and ready to have offspring. Any child they become pregnant with is carried to term in 5-30% of the normal time period (depending upon which generation a given breeder is, allowing them to have multiple children, extremely quickly. E-series units after generation three regenerate with shockingly fast speed, recovering from pregnancy and injuries therefrom in record time. Derived from the regenerative ability of Trolls, this ability is fueled by an incredibly rapid metabolism, which causes your average E-Series to require constant nutrition when not in stasis. Like their Echidna progenitors, E-series units have eyes with slitted pupils (like a snake's).
The children of E-Series units have pre-set genetic enhancements - all possess slightly higher than-normal muscle mass, reflexes, and bone density, as well as having a dramatically weakened - but functional - version of the E-Series regeneration, which allows them to recover somewhat faster from injuries. E-Series progeny are also blessed - and cursed - with developmental hyper-ability, causing them to age remarkably fast - a side-effect of their rapid metabolisms, intending to allow them to quickly reach maturity. This development and rapid maturation is as much mental as it is physical, but has several obvious drawbacks - most obvious being that most E-Series progeny have weakened emotional development; a second, but equally-critical issue is that said progeny rarely live to be older than 30, as their rapid aging kills them in short order. Such effects can be mitigated if the non-E-series parent happens to be extremely long-lived (such as an elf), which will offset the normal shortened life-span.
E-series units of generations 4-6 have a number of physiological traits designed to aid and support child development. E-Series units of the later generations possess particularly large breasts and are engineered to produce nutrient-rich milk in large quantities, to help foster development of their children. Their bodies, likewise, are engineered for their task; E-series units have wider-than normal hips and are, in every generation after the second, quite shapely. Generations five and six additionally possess a so-called universal pheromone that most humanoid species find pleasant; to most known species, smell like a female of that species in heat (even for species which do not undergo such periods). They all have extremely strongly-programmed maternal instincts, and if left idle when operational think of nothing but their intended task of having children. Ordinarily, their intelligence is quite low - they are little more than animals in this regard - but several (as was mentioned above) have exhibited the ability to think, speak, and reason.
E-Series units, due to their natural durability and regenerative capability, can live an extremely long time, though the lack of any E-Series units being in the wild has left most information on this as conjecture except for what's listed in lab reports. Barring unusual circumstances, a typical E-Series unit will live to be over 150 years of age - however the natural risks of child-bearing, paired with the fact that virtually all are biochemically aged to maturity and their naturally fast metabolisms mean most live only around 50 years at most. Verlaine is an exception to this - being the favorite of the head researcher of the Echidna Project, she was given an advanced series of genetic modifications designed to extend her longevity. Whilst it's uncertain how long she's got, UCI genetics experts believe that she could last as long as 300 years. Sjathrek, conversely, being a Gen-4, began suffering deterioration at the 29 year mark; had she not had further gene-therapy to treat it before it reached terminal, it's unlikely she would have lived more than another 1-3 years.
Genetic constructs dating back to the Ekris War, the Echidna Series, also known as the E-Series, was developed in an attempt to harness the innate abilities of the Echidna - a serpentine humanoid species famously known as the "mother of monsters." The project began when an expeditionary team in Renalia uncovered an intact (if deceased) Echidna specimen trapped in the permafrost on Mount Galdavi. Discovered by Renalian BioLogic, a large bio-weapon firm that was Renalia's chief competition with Appra's Genetic Weapon Division for super-soldier projects with the Mirandian Military. Immediately seeing potential in the extracted DNA, BioLogic attempted to create a means of mass-producing genetically-modified troops by taking advantage of the genetic mutability and rapid breeding cycle of the Echidna species. Functionally, this would allow a creation that could mass-produce offspring with pre-set genetic enhancements, regardless of species bred with, ergo allowing a wide array of different potential troops depending on what breeding stock was available. Even the most conservative estimates of the project listed that overhead for one E-series unit would be dozens of times less-expensive than a single EVO, and BioLogic successfully lobbied the Renalian government to supply funding to its research.
Initial attempts to insert Echidna genetic code into living humans (predominantly death-row prisoners) invariably resulted in fatalities as the subjects succumbed to organ failure and internal hemmorhaging, worsening as the subjects' bodies began to systemically break down from the inside. Initial forays into learning the cause of this was unsuccessful - until finally, one subject succeeded at surviving nearly a week, allowing BioLogic to ultimately determine the ultimate cause of the failures: The bodies of the subjects were quite literally being torn apart by their body's own attempts to reject their own altered tissue. After extensive deliberation, the idea arose to create subjects, based on the subject that survived a week, that would be born with Echidna DNA already inserted into their bodies, so as to make tissue rejection a moot point. The plan was successful, though initial subjects created by the Echidna project were barely even humanoid and most were wholly incapable of breeding. Later generations saw the refining of the project and dramatic improvements in offspring viability, resiliance, and recovery times. Each successive generation saw them look increasingly human - by generation 6 - the final production generation - E-Series units looked completely human save for bizarre hair/eye coloration and pupils that were slitted like a reptile's.
Disaster struck when a group of EVOs sent by Appra's Genetic Weapon Division sought to "deal with" BioLogic following their most recent contract bids. the EVOs destroyed the complex, killed most of the researchers, and made off with the bulk of the viable Echidna-series units and research data, leaving everything else to burn and/or rot. Biologic would never fully recover from this, and would cease to exist within 3 years, assuring the dominance of its main competitor.
As genetic constructs, E-Series units have no culture of their own and no purpose outside their intended one. Verlaine and Sjathrek are anomalies; the E-Series was never intended to be sentient, and the bulk of them have the intelligence of animals, content to serve their purpose as breeding factories. The overpowering majority of E-Series units wound up in the hands of Appra following the Ekris War; any further research on them conducted by Appra remains unknown.
The E-Series would later lead to the R-Series.