The Peseneyi are often said to be more alien than any of the other species native to the Ksreskézaian–Hogedepi Expanse
. Gifted with highly analytical minds yet limited bodies, they have gone to extensive lengths to craft for themselves every conceivable tool and convenience. For a time, the Pesenese Union
was a significant power in the Expanse, although it was dismantled by Khúsak
peace negotiators and eventually subsumed by the Ksreskézaian
A naked Pesene is similar in appearance to a quadrupedal arachnid with an unsegmented body and four eyes. Most Pesene 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.
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
, is exclusively oxygen-breathing.
Pesenese tissue does not consist of cells in the traditional sense; instead, hardened nuclei, connected to each other in a mesh through tubules, secrete enzymes and regulatory molecules through the tubule walls into the exoplasmic space. Segregation of function is performed exclusively by anchoring to the inside or outside of these tubules. The organism's exterior is usually lined with many layers of tubules. The non-motility of nuclear nodes following maturity means that redifferentiation to regrow damaged tissue is both efficient and critical; the Pesene generally injure easily.
They also have a unique central dogma: the primary chromosomal storage consists of complete inactivated proteins which are unfolded from their normal tertiary structure with detergents before being read by a polymerase. The identity of each residue is determined by its hydrophobicity and size, presenting many opportunities for replication error. Expression and epigenetic regulation are managed through binding factors that attach through hydrogen bonding to the head of the polypeptide.
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.
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; 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.