Anatomy and lifecycle
A naked Pesene is similar in appearance to a quadrupedal arachnid or crustacean with an unsegmented body and four eyes on stalks. Most Peseneyi grow up to 40 cm in body length at adulthood, although a small fraction of the population will grow up to 80 cm due to a common endocrine disorder. Each of the four legs is tipped with a small jointed claw that facilitates climbing on steep terrain, but most manipulation is done using a highly-developed tongue, which is tube-like and contains the aperture to the esophagus and lungs. Comparisons between the Pesene tongue and the trunk of an elephant are apt, although the Pesene tongue lacks the nasal septum and contains far more functionality.
Reproduction by the Peseneyi is essentially asexual; each individual is capable of self-fertilization, although as with many arthropods on Earth, the choice to reproduce is followed by a drastic reduction in life expectancy. Evolutionarily, a Pesene is expected to care for her young, and then to make way for them once they are sufficiently fully grown. As the risk of defects increases with age, the average age at which a Pesene commits to reproduction is 70 tgc, after which she will only live two or three more tgc.
Physiology and biochemistry
The Peseneyi originally developed in an oxidizing atmosphere on a planet that was undergoing a global deoxygenation event, analogous to, but the reverse of, Earth's Great Oxygen Catastrophe. As one of the few clades of motile heterotrophs that had developed at low altitude where oxygen concentrations were high, they were accustomed to oxygen exposure already; the resultant dip in biodiversity motivated an arms race of infighting until sentience was achieved. As such, the Peseneyi can breathe either ammonia or oxygen, but strongly prefer ammonia; their nearest relative species, the non-sentient koplazu of Illera, is exclusively oxygen-breathing.
The Pesenese biosphere has been studied extensively as a possible analogue to the "RNA world" hypothesized to pre-date Terran biology, although perhaps ironically, permanent genetic media in this case consists of protein analogues linked with peptide bonds, not saccharides. The primary chromosomal storage consists of complete, inactivated protein "prototypes" which are unfolded from their normal tertiary structure with detergents, then translated into a chiral mirror image by a highly sensitive peptide-dependent polymerase, sometimes called an anti-ribosome. The identity of each residue is determined by its hydrophobicity, chirality, and size, presenting many opportunities for replication error, but the chance of spontaneous mutation is very low due to the stability of the reference peptides. Expression and epigenetic regulation are managed through binding factors that attach through hydrogen bonding to the head of the polypeptide.
In the majority of high-copy proteins, the prototypes do not directly encode the sequence for the final protein, but rather another prototype protein, called the negative, which is copied to yield peptides with the same chirality as the original. Such self-mirroring proteins better resemble gene transcription in other systems, and are much more susceptible to replacement during gametogenesis; it is theorized that other, low-copy proteins are actually 'fixed' negatives that are produced by rare, spontaneous errors in the reference cap complex.
Pesenese tissue does not consist of well-defined cells. Nuclear organelles with a protein capsid are suspended in a regular cubic grid through a complex system of tubules, which function as both muscle fibres and blood vessels. Enzymes and regulatory molecules are secreted through tubule walls into a shared extracellular matrix, which functions primarily as a vacuole. The maintenance of microenvironments for specific enzymatic tasks is performed within conventional lipid vacuoles anchored to the outside of the primary tubules, and similar fibrous proteins are used to build up the body exterior. At maturity, nuclei have minimal motility, so clotting agents are stored uniformly throughout the matrix rather than circulating within the tubule environment. The Peseneyi generally injure easily and have an elevated risk of cancer-like prion disorders.
Like many plane-hopping civilizations, the Peseneyi are tireless technological, social, and philosophical progressives. The Pesenese Union, despite its imperialist tendencies, was founded on an ideology of the betterment of others, and did so effectively during its thousand-year existence.
Central to this is the Peseni phenomenon of imprinting, also known as codependent identity transfer by outsiders. Despite their asexual reproduction, the Peseneyi form a single key social bond with another individual, for whom they take on complete emotional empathy. Research has found a physiological basis for the capacity to maintain two potentially conflicting mental states at the same time, although the imprinted mind is never as strong as the other, and requires years to develop authenticity. It is believed this capacity originally manifested as a way to understand the point of view of others when the Peseneyi were completely solitary nomads.
This imprinting process is hence a powerful force which makes the political behaviour of the Peseneyi somewhat opaque to the uninformed. The Pesenese Union's earliest annexations were motivated by this profound empathy; successive acquisitions were a mixture of altruism and paternalism.
The primary way in which the Peseneyi improve themselves is through their machines. Every Pesene wears a robotic suit, called a gyeki; these suits have been sentient from before their exodus from Hava, and provide everything for their passengers, including physical strength, human-like speech, protection from the environment, size (most suits increase the pilot's height to about four feet), and waste filtration. As the technology in these suits advanced, it became increasingly common for a Pesene to imprint on them, making the two essentially symbiotic. The suits themselves do not experience imprinting, although they are programmed to be very protective.
The Pesenese outlook is not always tolerant. The dominant ideology in their culture has always been improvement at any cost, and they are frequently seen as do-gooders and meddlers with pure intentions but little sense of respect for the autonomy of others. Philosophically the Pesenese developed very advanced concepts about dignity and moral relativism around the time of their exodus, but had no concept of democracy, legal self-determination until they first encountered the Khúsak. It is common to hear the Peseneyi described as "help first, ask for permission later." This has caused several minor wars.
Ontologically, the Peseneyi are atheist, arguing that no higher power of any consequence would choose to leave the universe in such a disarray. Early historians maintained that the Pesenese used lack of religion as a weapon, to destroy the theocratic states on the worlds they occupied, but the only verifiable records are of individuals being convinced to abandon their religion by emotionally conflicted imprinters, not whole populations. In general this attitude has made them great explorers of the stars; they had mapped the whole Expanse, and beyond, long before the Ksreskézai and Hogedep were capable of travelling between branes.
The Peseneyi are from a brane called Hava, known primarily as the site of the Hava Vortex, a supermassive gravitational singularity that consumed their native system in 12068 lky. They escaped to Hromo, a nearby uninhabited brane with four stars, and terraformed all nine planets into ammonia-rich reducing atmospheres more comfortable for their biochemistry.
From 62593 to 62914 lky, some time before the start of the Grand War, a multi-brane coalition called the Pesenese Union spanned large portions of the Expanse. Relatively little record of it survives to the present day, but it was sometimes said to be "sustained by xenophilia" and the unique practice of imprinting by Pesenese diplomats onto members of other species. Despite its populist name, the Union disintegrated after Khúsak political theorists introduced the Pesenese to the concept of the consent of the governed, resulting in a wave of secessions by encompassed worlds.
Some time after this, a faction of gyeki suits evidently felt the same way, and became a distinct culture known as the Epyesteyi (sg. epyesti). The Epyesteyi returned to Hava and primarily inhabit Makta, although they can be found wherever the Peseneyi are or have been, and often take up residence in locations built for the Peseneyi but no longer used by them, including some cities in post-Shattering Thet.
The Peseneyi were the first to discover the vacancy of many formerly Tletketti-held worlds, including Wanisin, and they were the first native sentient species of the Expanse to make contact with non-egrekeloid humans. The Lyrisclensiae, Telai, and Hatel all made strongly positive impressions on the Pesenese, and consequently they are often said to be more interested in humanity's past than humanity is. Figures from human history who resonate with Pesenese ideals, such as Pythagoras, Friedrich Nietzsche, and Yakov Emmet are considered on par with, or even above, their Pesenese counterparts in terms of cultural significance and reverence; in particular, there exists an obsession with the twentieth-century astronomer and science communicator Dr. Carl Edward Sagan (1934–1996) that is completely incomprehensible to outsiders. Saganiz (/se.'ǂe.ɲɘz/), or "Saganism," is used as a catch-all term to describe everything from general optimism about strangers to a specific sense of spiritual oneness with the stellar lifecycle.