A long, long time ago, when AOL was still king of online roleplay, two characters, an Alchemist and a Wanderer, were messing around with chemicals one day when they accidentally created a mutated lizard that became the prototype of the leupak. Since then, leupakian psychology has generally gone in one of three directions:

• Highly social innovators whose curiosity frequently leads them towards scientific pursuits, often regardless of the consequences.
• Egotistical psychopaths that want to convert everyone into stretchy egg sacks for their babies to burst out of, and who attempt to take over their stretch of the world roughly once a month.
• Cynical isolationists who are constantly at war with the world because they're mistaken for the egotistical psychopaths.

Of course, these are all gross oversimplifications of the depths of the leupakian psyche – but depictions of the leupak in popular media tend to focus on one or more of these aspects as a shortcut when stereotyping them.

The original creators of leupaks were Nefirian Phoenix and Arc Legarro, entirely by accident. Nefirian attempted to use these creations to conquer the various countries and worlds he inhabited, with varying levels of success; Arc Legarro mostly attempted to curb their more sinister impulses and make up for having inadvertently created the whole mess, and give Nefirian another chance when the individuals, countries, or deities he managed to offend caught up to and killed him yet again. While the legend of the Phoenix still exists in the lands he once sought to rule as a god, the man himself is difficult to locate, although it is said that some of his clones have escaped into the wider multiverses to seek divinity and rulership over other worlds.

The next major advancement in leupakian science came at the hands of Shawna Tiempra – at one time, a warrior turned priestess to the dark and terrible god of the Void, and eventually a scientist as she began working on biological warfare agents based on the original leupakian designs. Over time, her view on the world and the lives within it has softened, and she is currently one of the realm's staunchest protectors, as well as the de facto 'Mother' of the leupakian race to this day, continually working on advancements in leupakian bioscience to better the lives of her citizens and the rest of the world.

The third major advancement in leupakian bioscience came at the claws of Gulak – an ambitious leupak with dreams of becoming the evil god the planet needs to balance out the forces of good. His attempts to declare dominance in territories deep within the heart of peaceful kingdoms eventually resulted in massive deaths, disruptions in leadership structure, and the eventual collapse of the region into anarchy – although ironically, he was driven from the lands before he could make good on his attempt to claim it for himself and his creations.

In the modern era on their homeworld, leupakian bioscience is actively developed by the leupaks themselves, who seek to customize their genetic structure to meet the needs of the environments they must face. With genetic restructuring and consciousness backup and transfer technology, they have developed a region where death is temporary and the excitement of discovery is the true motivator of civilization. They have also managed, thus far, to keep the territories of Eio and Tiemprest both free from foreign rule and integrated into society, and are staunch followers of the goddess of reptiles, Alshira, the Dragon Goddess.

In realms outside of Arcydea, the world where leupaks and various subspecies such as jakoks and leupai were first created, the concept of the leupak has met with mixed success, depending on which psychological evolutionary path they adopt and whether the locals are into that sort of thing.

While leupaks have an extremely flexible genetic structure that makes them difficult to pin down, most leupaks have some basic traits in common:

• Leupaks, whether humanoid or otherwise, are usually scaly. Some leupaks exist with scales small enough to be difficult to distinguish from ordinary skin, with the exception that it does not shed in flakes, and certain offshoots have combinations of scales and fur or feathers.
• Leupaks are highly predisposed towards psionics, and may be innately talented at it or capable of developing it through training. Depending on the leupak in question, this may mean anything from someone who holds polite mental conversation with you while sipping from a glass they are holding in the air with telekinesis, to someone who slams you against the wall with their powers while trying to rape your psyche into submitting so that they can use you as they see fit; some evolutionary branches are more predisposed towards one over the other.
• Leupaks have flexible skin, innards, and musculature. This means that they are capable of squeezing into tight spaces, and also means that they tend to be capable of changing body type more easily than most with less difficulty.
• Leupaks have a prehensile tongue. This is named a tongueclaw, because the tongue features claws that act as grasping appendages. The tongue is also muscular and hollow, with an aperture that allows the leupak to draw in food directly without impairing its breathing. Depending on the species, a tongueclaw can have as much dexterity and strength as any of the other limbs, or may require other limbs to hold prey still.
• Older leupakian species and some major evolutionary paths of modern leupak consume blood as a dietary supplement, although most leupaks can now ingest other foodstuffs as well for nourishment. This is typically achieved by penetrating the flesh using the tongueclaw, and using the muscular tongue to suck the blood or other material out like a straw.
• While modern civilized leupaks have been given the ability to achieve sexual reproduction, most leupaks have the ability to generate eggs, and to implant their eggs directly into a subject by using their tongueclaw as an ovipositor. The effects of this depend on the leupak species, but as a general rule, it is unpleasant or fatal for the host as they typically are implanted in the abdominal cavity and rip their way out of the sternum when ready to 'hatch', and many species of leupak are designed to implant multiple eggs which may all successfully reach the juvenile stage. Leupaks are more capable of surviving this process, although most leupaks prefer a partner. Medical procedures to promote the survival of both host and offspring are possible.
• Although some species of leupak have specific male and female genders, most leupaks (particularly non-humanoid leupaks) have no biological gender to speak of (they are capable of producing eggs, and can also host them). Oddly, leupaks with no biological gender are more likely to assume traditional gender roles (a masculine role of finding others to impregnate, and displays of dominance; versus a feminine role of mothering offspring and collecting a brood), whereas those who have the ability to choose a biological gender tend to be more agendered in mindset, choosing whatever suits their current purposes and enjoyment.
• The genetic elasticity leupaks possess, as well as the procedures used to transform them, mean that leupakian nature may be contagious depending on the species. Some older species have the ability to generate a slimy substance that acts as a mutagen capable of poisoning a potential host or rewriting their genetic structure to effectively asexually reproduce through transmogrification. While this is mostly not prevalent in modern leupakian design, this means that organ transplants between leupaks and other species are more likely to succeed without rejection, although at the risk that some leupakian traits may influence the host.