A kirin (麒麟) is noble and holy creature that is bound to and chooses the ruler of each kingdom according to the will of Tentei, the Emperor of Heaven.
As creatures of benevolence, a kirin serves as a monarch's advisor until the monarch's death and will bow only before its ruler. No matter if the kirin objects they cannot go against their master's orders, even if that means killing someone. Should a monarch lose the way and begin to govern in a way that violates the mandates presented to them upon ascending their throne, their kirin will be struck with an illness known as shitsudou. The disease is often fatal and the death of the kirin will result in the death of their monarch soon afterward; however, should a monarch manage to return to the way or renounce their throne and die, a kirin can recover from shitsudou to search for a new ruler.
All kirin are born from a special tree on Mount Hou known as the Shashinboku and are protected by female youma known as nyokai, which are born solely for the sake of caring and serving a kirin. After hatching, they normally spend several years upon the sacred mountain cared for by the female sages who reside there, led by Gyokuyo. At birth, kirin possess the form of creature resembling a hybrid between a horse and a deer with a single horn from its forehead, somewhat like a unicorn. Kirin typically possess long golden manes and pelts that shimmer in paler shades of gold. In rare cases, black, red, or white kirin may be born. Kirin can shift into human form, usually as an individual with long golden hair matching their mane in beast form. Immature kirin are known as hina (雛, fledgling).
The lifespan of a kirin is no longer than thirty years (without a king). There have been only eight cases where a kirin died without fulfilling its primary purpose since the creation of the world -- the most recent being the Enki that came before the current Enki. A kirin's physical form ceases to age upon reaching maturity, usually when the kirin ascends to their kingdom's palace above the Cloud Sea.
When a kirin finds its monarch, they give an oath: "I swear never to desert my post before your throne."
By nature, kirin abhor the scent of blood, and killing a person near a kirin or even just the sight of blood will greatly weaken it. In severe cases, a kirin may suffer from "blood sickness", which includes symptoms like fever and vomiting. Because they are adverse to violence, kirin are served by shirei, creatures they make a pact with that will fight for and protect them.
A kirin's source of power is the single horn that is located on the forehead. Kirin, in both human and beast form, loath people (with the possible exception of their ruler) touching their horn. The horn is what allows them to tame youma, shift forms, and many other miraculous deeds. Horns vary from kirin to kirin; some have three prongs while others have two. While in human form the horn is only visible as a light freckle. If the kirin's horn is bound, they are rendered powerless, especially if it is done so while the kirin is in human form.
Among other abilities, they are known to be the swiftest creatures in the world, capable of riding upon the winds. They are able to create meishoku, smaller localized versions of shoku, great storms that frequently bring kaikyaku to the Twelve Kingdoms. The meishoku allow kirin to travel between Hourai and the Twelve Kingdoms with the least impact on both worlds.
Each kirin is named for the kingdom it serves, with the suffix "ki" 麒 appended to the names of male kirin and "rin" 麟 appended to the names of female kirin. Kirin do not normally possess given names of their own, though Enki and Taiki have names because they are taika born on Hourai. A kirin may be granted names by their rulers; the current Sairin was named Youran by her monarch.
A kokki (黒麒) is a black kirin and are extremely rare. They are thought to bring good fortune to its kingdom and are born only once every couple hundred of years. Taiki is an example of a Kokki.
Black kirin like Taiki are described as having ebon pelts like fine-polished steel, a pearly horn, and a silver back speckled with mica.
The following kirin have appeared in the Twelve Kingdoms series.