The world of Dunia has two ancient ancestral species, capable of sapience, that determine certain base characteristics of that species' descendant races; the Fay and the Sifir.
The sifir are animal-like, like the dru'un and kuna, but are not animals as they are sapient. They are not always straight animal-like, which is shown by the illim and the kwugra, who both resemble no known animal.
Sifir species generally reproduce sexually, and before the Trifolk Alliance, only with their own particular species. They are all able to interbreed and have offspring with one another, producing a child that is either one species or the other. The sifir-descendant species cannot have mixed offspring with one another. In the Kykr civilisation, three sifir species live intermingled with one another in mixed relationships.
Sifir species are commonly of average intelligence, albeit at different levels of development and technology. Particularly the dru'un and hessak are both behind in societal advance and thus lack the drive for complex thinking. Because of this, they are considered lower in intellectual development. The kuna are among the smartest and most devious sifir species.