There are four broad categories of living beings that exist in Arvastaira: the arva, the fenva, the dalvakin, and the dalvarun.
These distinctions are more or less drawn by how many forms the entities can shift into.
The specifics of formshifting are discussed in another guide here.
The arva, the many-formed with infinite forms, is a category that consists primarily only of deities. There have been rumours of mortal arva before, but those are regarded as old wives' tales more than documented history. Regardless, the phrase arva is used to indicate the divine class of entities that hold Arvastaira together, and for the sake of this guide, we will only be referring to the divine when we use the term arva. A note, though, that the word is interchangeable with "the divine" and "deities", and arva is a very archaic and formal term, unlike the other classes of entities.
An arva has many, nearly limitless forms they can take on. Not only can they become any variety of creatures, both magical and common, but they can also take on limitless variations of fenva forms, even mimicking the appearance of an existing individual.
In their true forms, arva are draconic by nature. However, the more draconic features they take on, the more keirsi radiates off of them, making any other living creature unable to exist near them. As such, most arva often appear as fenva to contain themselves accordingly.
Being of Atei's direct bloodline, they are effectively immortal, unable to die from anything short of another arva level entity's most powerful sorcery. To date, no arva have been truly killed. The result of an arva dying would be catastrophic for Arvastaira. The sudden, violent release of keirsi would result in unimaginable amounts of destruction, with the death of an older arva having the potential to wipe out all non-arva life in existence just by itself. It is unclear whether Atei would intervene to prevent such an occurrence.
The fenva, the many-formed with finite forms, is a category that consists primarily only of fenva and fenva sihanvin, or fenvasi. While there are exceptions, almost all fenva naturally appear as pointy eared humanoids, so in this guide we will refer to the most common use case of the term. There is also a distinction between fenvasi by birth who have undergone evansurana and those who have not. Most of a fenvasi's enhanced traits result from the ritual. Thus, if they have not undergone it, they are simply regarded as more powerful fenva.
Fenva are simply the human equivalent of the world. Fenvasi, on the othehr hand, are the product of magical interaction between a mortal and a deity. There are at least a couple hundred of them in existence at any given time. The main visible differences between a fenvasi and a fenva are their physical attributes. Fenvasi are unable to die from disease or old age and their bodies can withstand more trauma. Their physical age progresses much more slowly, and they heal from serious injuries much more readily than fenva, usually taking no more than a week to recover. Fenvasi are also unable to reproduce or conceive offspring by any means due to the nature of their soul. As it was formed through their arva parent's keirsi instead of regular means, they are effectively infertile.
In addition, arva also have access to rosvoms, which are covered in the sorcery section here.
On average, the fenva have three forms they can shift into besides their natural form. These usually consist of a land form, aquatic form, and aerial form. It's not uncommon for them to have more or less than three, but attaining new ones through will alone is almost impossible. Still, they are able to experience multiple forms to adapt to their needs and are the second most populous group of entities in Arvastaira.
Formally known as dalva kinsoruun and dalva runsormus, these entities only possess one non humanoid form and are unable to shift properly. Some say this is due to them being an afterthought by Atei in the creation of the universe while others say it's because their direct creators, Somina and Onnvuset, are wholly satisfied with the forms they made and did not see fit to allow tampering in regards to their perfect ideas.
The dalvakin are intelligent one-formed creatures that are capable of speaking the Arvastairan tongue. They can have intellect ranging from primitive to rivaling or surpassing that of the fenva. Dalvakin are quite rare compared to the dalvarun, with only a couple thousand in existence. They typically live in very isolated groups, not wanting to interact with any other type of entity in Arvastaira.
Dalvakin are subdivided into magical and common variations. Usually, dalvakin are magical creatures. Magical dalvakin are able to manipulate keirsi in similar manners to a sorcerer, while their rarer counterpart, common dalvakin, cannot.
The dalvarun are unintelligent one-formed creatures. They do not have logic or language to follow and generally act based on pure instinct.
Like the dalvakin, dalvarun also come in magical or common varieties. Despite not possessing a refined mind, magical dalvarun are fully capable of manipulating keirsi for deadly attacks. However, these attacks typically lack nuance, control, or intention that is only seen in other types of magical entities.
Almost all Arvastairans fall under one of two major alignments. Dictated by a mix of personal belief, geographical location, and the method with which you are able to interact with keirsi, most fenva and arva fall under the label of the lumena or vesera. Persecution and shunning of those who do not fit the faction of their geographical location is not unheard of. One's alignment for keirsi manipulation is mostly determined by lineage, but variations do occur naturally. In many ways, these two factions seem like two sides of the same coin.
This faction worships the deities of Resovinasis. Their origins lay with the belief that each person has an opportunity to challenge the fate set forth by Atei. Order and free will were key tenants of this faction's creation, and the guiding principle is to deliberately discover oneself throughout life. The lumena people are generally less concerned with bloodline or family ties. However, the lumena gods have a very strict hierarchy for both themselves and fenvasi, dictated by familial ties.
Historically, the lumena usually occupied slightly more land than the vesera. In comparison, they have more natural resources and a lower population, with the density being spread more throughout their territories.
This faction worships a single deity, Karas. Their origins lay with the belief that each entity was brought forth with a destined role to fulfill in the world, and that they should embrace whatever life gives to them. Chaos and fatalism were key tenants of this faction's creation, and the guiding principle is to always know oneself and live truly around that understanding. The vesera people are generally very proud of their bloodlines and family trees, shunning orphans as well as illegitimate children. However, the vesera god Karas does not produce many children himself, choosing instead to adopt them as he sees fit.
Historically, the vesera occupied slightly less territory than the lumena. In comparison, they have a a larger population and their population density is far more concentrated in specific regions.
Some people are born with a mutation that allows them to utilise both vesera and lumena techniques to interact with keirsi. One with this ability is referred to as a neveniati, or neven, and they are often seen with strange purple splotches on their bodies after casting. No matter the faction, to be a neveniati is to be shunned and feared. Historically, they have a long record of causing widespread devastation due to a lack of control over their powers.
Any neveniati that is lucky enough to quickly understand their lot in life will conceal their abilities as much as they can, using the faction's preferred form of magic and hoping to live a normal life. But many neveniati lose control of their powers and are discovered, namely from the telltale purple splotches that grow all over their skin after exerting themselves magically. In those instances, they are usually put down, exiled, or subjected to an array of other negative outcomes.