Spirits were a race of supernatural energy beings that inhabited Alagaësia. They preferred to remain neutral in all affairs though on at least one occasion they gave gifts to people such as the golden flowers for the release of the spirits trapped in Durza.
Spirits had no definite form or appearance and could, assumedly, take the appearance of anything they wished. The spirits that Eragon and Arya saw were orbs of color. Their magic power also seemed to rival the dragons, though they seemed to be able to use it more easily and consciously than the dragons were able to. They also possessed great mental strength, with the ability to simply power through Eragon's and presumably Arya's mental barriers, even though they both are very skilled in defending their minds.
Role in the Rider WarEdit
In Brisingr, a group of spirits came into contact with Eragon and Arya. Arya told the spirits that Eragon had freed the spirits in Durza, causing one of them to search through Eragon's mind before producing golden flowers for them as a reward.
Some time after the formation of the Dragon Riders, a group of humans discovered that they could call upon the spirits and accomplish the same feats as magicians through them. They became known as sorcerers or sorceresses.
However, sorcery was not without its dangers. If a person tried to call upon a spirit greater than he could master, the greedy spirit would possess the individual, creating a Shade (some Shades were also created by ambitious sorcerers greedy for more power allowing themselves to be possessed by evil spirits). Shades were immensely powerful (yet wicked) and could only be killed by an attack that pierced their heart.
There were only two Shades known to be alive during the Rider War. The first was Durza, who began life as a boy named Carsaib. Carsaib, an orphan, was taken in by a sorcerer named Haeg and taught to use spirits: however, when bandits attacked and killed Haeg, Carsaib summoned spirits in a rage. He was unable to handle the spirits he summoned though and succumbed. The resulting Shade, Durza, played a major part in the Rider War until the Battle under Farthen Dûr, at which point he was slain by Eragon, after a distraction provided by Arya and Saphira. During the Siege of Feinster a second Shade named Varaug was created by three sorcerers, but was soon slain by Arya, with Eragon's help.