Races of Alagaesia

Humans

The human culture was agrarian; most humans are farmers and peasants, and their technology is fairly primitive. Different regions have different customs and traditions. Some areas, such as Kuasta, are so isolated by the Spine that their inhabitants are considered somewhat odd by people from more urban areas. Most humans seem to believe in some sort of fate or divine influence; most are superstitious. Several possess magical or psychic powers; some are wizards or witches, others become Dragon Riders.
Traveling merchants are the primary source of news for many villages, as most people never travel very far from their birthplace in their lifetime.

Humans make up the majority of the citizens within Alagaesia.

Dwarves

Dwarves (Knurlan in Dwarvish, singular knurla and Dvergar in the Ancient Language once known to all creatures) are one of the only races native to Alagaësia. Known as lovers of rock and stone, dwarves have a long lifespan and often live in large, underground cities in the Beor Mountains. One of the most famous dwarf cities is located in Farthen Dûr ("Our Father" in dwarvish). The city itself, Tronjheim, was the secret hiding place of the Varden up until the Battle under Farthen Dûr. The dwarves have many clans such as the Dûrgrimst Az Sweldn rak Anhûin and the Dûrgrimst Ingeitum. With the fall of the Empire the Dwarves were accepted into the Dragon Riders along with the Urgals.

Dwarves are second most common of the four rider alliance races.

Elves
Elves are a race of beings who migrated to Alagaësia from Alalëa in the distant past; around 5217 AC. Humanoid in appearance, they have noticeably angular features, slanting eyebrows, and pointed ears, and a feline face; they are generally tall and always slim, and are, according to legend, the fairest people of the land, partly because of the physical transformation caused by the dragons' influence on them (and are thus called the Fair Folk). Most elves are more greatly gifted with magic than the other races, and had an innate knowledge of their true names, thus being more powerful than other races.

Elves are the least common of the four rider alliance races.

Urgals

Urgals (or Urgralgra in their language), are a race of sentient creatures that inhabit Alagaësia. They are considered evil by most humans, but are not inherently so. Though most are uneducated in the normal definition of the word, they make up for this with brute strength, exceptional combat and commanding skills. They were used as expendable "shock troops" of Galbatorix's army. The Urgal language is a simple, guttural language. Only a few phrases are known to outsiders, and most of those are related to war and combat. As with most other races they are capable of using magic, though even more rarely than the dwarves or humans. With the fall of the Empire the Urgals were made Dragon Riders along with the Dwarves.

Urgals are the third most numerous of the four rider alliance races

Ra'zac

The Ra'zac (or Lethrblaka when full-grown) are one of the several ancient races that were thought to have followed the humans across the sea to Alagaësia. They were a race that feed on humans and likely came from the same homelands. Ra'zacs' breath has the power to paralyze humans in a dream-like state, however, it barely clouds the minds of dwarves and is ineffective against elves altogether.

The Ra'zac are nearly extinct, and the few that exist are abhored by almost every race. Urgals will typically leave them be, but other races do not.

The Ra'zac cannot use magic. The Ra'zac are known to be mortally afraid of water and the sun, as they cannot swim and sunlight burns their skin and eyes.

Ra'zac are the least common of all the sentient races in Alagaesia

Werecats

Werecats are sentient creatures with shapeshifting abilities, being able to take on the appearance of either a human or a large, shaggy cat. Whether they migrated to Alagaësia or were native to the land is unknown. They are quite rare; the few who were alive during Eragon's time did not often reveal themselves.
Werecats were said to be very smart and dangerous at times.

In Inheritance, it was revealed that werecats can command regular cats as well as their own kind.

Werecats are less common than any of the four riders races, but more common than Ra'zac

Dragons

Dragons are sentient creatures that roamed freely in the land of Alagaësia. They were the mounts and life-long companions of the Dragon Riders. Apart from werecats, spirits, Nïdhwal and Lethrblaka, dragons are the only known intelligent non-humanoid species.

A player may only play as a dragon if they are with a rider. Different players may play a dragon and rider if they wish.

Lethrblaka

Lethrblaka is the adult form of the Ra'zac. In the Ancient Language, their name means "Leather flapper". They could hunt anything in Alagaësia. Oromis stated in Eldest that it was strongly believed by the Riders that the Lethrblaka had followed the humans to Alagaësia. Only two of these creatures survived the Ra'zac War. The humans tried to eradicate the Ra'zac and Lethrblaka as quickly as possible. Two Lethrblaka escaped and laid eggs. The remaining Ra'zac and Lethrblaka (two of each) worked for King Galbatorix because he made a deal with them to work for him in exchange for their favorite food (humans). Oromis stated that they are cruel, twisted creatures, somewhat similar to dragons. However, they are described as being something akin to a twisted, cunning, evil dragon, and are probably not actually related to dragons.
The Ra'zac used the Lethrblaka (their parents) for reaching places that would otherwise be inaccessible, such as their lair in Helgrind, where the Lethrblaka lived with their offspring.

One of the only things useful against Lethrblaka is magic, thus only a Dragon Rider on his/her dragon would have a fair chance of killing them.

A Ra'zac player may use a rider token to become a Lethrblaka

Shades

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.

Shades are many times more fit than humans, more so than even elves, and have outstanding command over magic. Players of any magical race may become shades by using a Rider token if they use sorcery, or start as a shade by using a token.

Dragon Rider

The Dragon Riders (Shur'tugal in the Ancient Language) were a coalition of elves and dragons formed at the end of Du Fyrn Skulblaka to forge peace and order between the elves and dragons. The Riders were created because treaties between the two races would prove useless to stop fighting: a signed piece of paper meant nothing to a dragon. So, an irrevocable bond was wrought by the elves and the dragons; the elves provided the structure of the spell and the dragons provided the strength, thus creating the Dragon Riders. When a fleet of humans sailed across the sea thousands of years later, they too were added to the elite order of the Dragon Riders. The role of the Riders became more than uniting the Elves and Dragons: they became keepers of the peace throughout the land of Alagaësia, and were respected and honored by the people they served. There were both male and female Riders, all of whom were able to use magic. The Riders not only were peacekeepers, they were healers, scholars and the strongest magicians throughout the land besides Shades. Recently, both Urgals and Dwarves have been added to the pact.

A player may use a rider token to upgrade an elf, human, urgal, or dwarf to a rider, or create a new character of one of these races to be a rider.