Codex Alera

Codex Alera is a fantasy book series by Jim Butcher. The series chronicles the coming-of-age of a young man named Tavi in the realm of Alera, an empire similar to Rome, on the world of Carna. Every Aleran has some degree of command over elemental forces or spirits called furies, save for Tavi, who is considered unusual for his lack of one. As the aging First Lord struggles to maintain his hold on a realm on the brink of civil war, Tavi must use all of his intelligence to save Alera.

Alera is part of a large continent that is inhabited by the Icemen to the north. They are connected to another large continent held by the Marat via a land bridge, which is the location of the Calderon Valley. The Canim reside across the ocean to the west, staging regular, bloody raids on coastal settlements. A map of the realm, illustrated by fan Priscilla Spencer, was published in First Lord's Fury.

The inspiration for the series came from a bet Butcher was challenged to by a member of the Del Rey Online Writer's Workshop. The challenger bet that Butcher could not write a good story based on a lame idea, and he countered that he could do it using two lame ideas of the challenger's choosing. The "lame" ideas given were "Lost Roman Legion", and "Pokémon".

Furies are elemental spirits (earth, water, air, fire, metal, and wood) that inhabit all aspects of Alera. Some are small and cannot be seen, and others are powerful enough to manifest when called upon by their wielders. There also exist "Great Furies," the most powerful and ancient of these spirits, by which Alerans swear and curse. They manifest as geographic formations of great elemental power, such as volcanoes and oceans, and are far more often restrained or provoked than explicitly commanded, and then only by fury-crafters of exceptional strength. Many Alerans are unaware of the Great Furies' actual existence, imagining them to be more mythic than real, but this disbelief is incorrect.

While Proto-Aleran ruins show no sign of fury-crafting ability amongst humans of the past, the Aleran people at the present day manifest personal furies in their early childhood or adolescent years, and control them with their minds. They are used to aid them in whatever task undertaken from housework to combat. This fury-based magic is accomplished in one of two forms. First, an Aleran may draw from the strength of their fury to increase their own. For example, earth crafters often draw physical might from the ground, through their furies, to allow them to lift loads far too heavy for normal people, while wind crafters can increase their speed and metalcrafters their endurance. The second form of fury-crafting is to "manifest" a fury. This involves the fury taking a visible form, often the shape of an animal, though taking the shape of a human is not unheard of. Manifested furies are necessary for the most powerful forms of fury-crafting, including flight (windcrafting) and healing (watercrafting).

...
Wikipedia