Centaurs are immortals with the lower half of a horse and the upper half of a human.
The immortals live in tribes, or herds, in the forests and come out to trade with villages and towns. To keep centaur females pleased males must constantly give them gifts otherwise they may be mobbed or abandoned. They also do not balk at slave trade and have offered to buy strong human females such as Keladry of Mindelan and also regard horses as slaves. Comments by Graystreak in Squire suggest that centaurs can and do breed with both humans and horses
Centaurs generally cull those who they consider to have bad blood. On top of this, they believe that any slave (horse) that has been mounted by a male centaur with bad blood is tainted as well, and they are killed as well. However, only the herdmaster of a tribe has the right to give the order to cull. Should he be unwilling to do so to a centaur, they may be forced out of the herd. The slaves are killed regardless of this decision.
Being sentient, centaurs are not necessarily good or evil. Even the so-called "peaceful" centaurs will participate in raiding and banditry. Centaurs personality depend on the individual. When they took loot from a village, they would gallop off, then bury the treasure so that they would have a lighter load.
Centaurs have their own deities. The only ones named are the Mares with Bloody Teeth, their goddesses of vengeance.
There are two kinds of centaur, described as peaceful and killer centaurs respectively. While both have human torsos attached to horse bodies, the former have hooves, while the latter have talons. However, the description "peaceful" is a bit of a misnomer and is only in relation to the other kind, as these centaurs still have an incredibly brutal culture.
Their human parts can look like any race of human, just as their horse parts can be any color natural to horses. Centaur hooves are slightly but recognizably different from those of mortal horses. They also refuse to wear horseshoes. Centaurs of rank wear a great deal of ornamentation to show their wealth, including jewelry on their legs. Tail braiding is not uncommon.
Centaurs age for the first two centuries of life, then stop after reaching maturity like other immortals.
Their noses are sensitive enough to locate a man if he doesn't disguise his scent.
Should one acquire a hair from the tail of a centaur, great control is gained over them. It is implied that burning the hair would cause them intense pain, if not kill them.
Centaurs have stronger human bodies than mortals to match the strength of their horse parts. In a fight, they kick and bite as often as they use weapons. Most are also skilled archers, with Raoul of Goldenlake stating that he has never seen one miss. On top of this, they prefer to fletch their arrows with griffin feathers (known to increase the accuracy of arrows) and those of other immortals, which can have varying effects. They never use crossbows, considering them to be beneath their skill.
Centaurs can also use magic, although it is unclear if they have mages like humans or all have some ability like Stormwings. It can be used as battle-magic or to hide themselves from trackers and scrying. It appears as brown and gold fire.
- Graystreak - herdmasters of the centaur herd near Haresfield in Tortall. His human body is that of a light-skinned man in his fifties with black and grey hair, while his horse parts are those of a blue roan.
- Iriseyes - a female centaur who helped hunt the Haresfield renegades
- Maresgift - leader of the Haresfield renegades. He is Graystreak's brother. He was beheaded at Fort Irontown after he was captured at Owlshollow.
- Jealousani - a centaur member of the Haresfield renegades. If he survived the battle at Owlshollow, he was beheaded at the trial afterwards.
- Edkedy - a centaur member of the Haresfield renegades. If he survived the battle at Owlshollow, he was beheaded at the trial afterwards.
- Windteeth - a centaur member of the Haresfield renegades. He murdered a peddler who had kidnapped a baby griffin, then took the griffin for his own. He was killed trying to escape Owlshollow with a child by Keladry of Mindelan. His brother was also one of the renegades.