The majority of Terra's civilization consists of the Ancients: a conglomeration of sapient races consisting of those resembling the Homo sapiens of Earth with the body parts of various animals, legendary creatures, and mythological beings in our world, notably ears and tail; and bipedal, sentient animals/legendary creatures/mythological beings.
Certain humanoid Ancients have two pairs of ears, one human and one animal, and both are functional. Furthermore, the Ancients' humanoidism and anthropomorphism are apparently not tied into their bloodline, which can be explained by the anthropomorphic Rat King having a humanoid daughter (Lin Yühsia).
The term human and its derivatives are typically used to refer to the Ancients as a whole; "Ancient" itself is only used in technical circumstances by the Terrans. Despite this nomenclature and the fact that humanoid Ancients share a superficially similar appearance with Homo sapiens, both are completely distinct races.
Cross-racial breeding seems to be common among Ancients, though it seems that they prefer breeding within races with similar traits, i.e., Wei Yenwu (a Lung) and Fumizuki (a Kirin); Severin Hawthorn (an Elafia) and Tatjana (a Caprinae) as family members. An offspring of a mixed race tends to inherit the traits of one of their parents instead of both, and this is especially prominent in the Sankta race. However, whether there are extreme cases of breeding with a totally different race (such as a Forte and a Feline couple) remains unclear, and so does how it will affect their offspring.
Relevant Subraces:
- Lupo - individuals with lupine (wolf) features: usually the ears and tail, sometimes fully anthropomorphic. They are among the primary races found in Siracusa.
- Vulpo - individuals with vulpine (fox) features: usually the ears and tail, sometimes fully anthropomorphic. They are among the primary races found in Siracusa. A nine-tailed variant is known to occur in Higashi.
- Durin - the equivalent of dwarves: short of stature (around 3' tall usually) with pointed ears. They are a mysterious race that little is known about, due to their subterranean lifestyles, but are known to capable of drinking other races under the table.