The Rodians are believe to be descended from ordinary rats found in every major city of every race. It is not known how these rats ultimately became intelligent, but it seems likely that some powerful magic or Gods were involved.
They are first mentioned in Dwarven sources approximately 6000 years ago, some time after the Dwarves first began trade with the surface races. The Dwarves and Rodians were immediately terrible rivals, and the Dwarves lay the blame of the Rodians existence squarely at the feet of surfacers.
The early history of the Rodians is dominated by a long series of wars with the Dwarven holds. The Rodians always seemed to come up short in these early wars, with the Dwarves butchering scores of the rat men for every Dwarven life lost. It was only 1200 years ago, after the events of The Sundering, that the Dwarves and Rodians finally reached an uneasy, if somewhat intermittent peace. Today, Rodians are found in virtually every major city of every race.
Rodians are much smaller than Humans or Elves, typically around 1 meter tall and slight of build. They are very fast and possess an intelligence that can surprise others who judge them based on appearance. Rodians live short lives of at most about 50 years. Although some Rodians do have a talent for magic, they simply lack the time needed to become great mages.
Rodian culture tends to value the clan or family unit very highly. Individuals, even ones of some status are usually seen as expendable, as long as the clan survives. Rodians reproduce extremely rapidly compared to the other civilized races, but their numbers are kept at least somewhat in check by very high mortality rates due to constant infighting. Even so, some scholars suspect that the total Rodian population may easily be ten times that of all the other races combined - enough to easily control the entire world, if they banded together.
Rodians form under-cities in every city they live in, rarely building their own cities or buildings. They will inhabit sewer systems, slums, and dungeons - wherever there is space in a city. Living under other races (especially Humans) in this manner means the Rodians typically do no have any government or authority of their own. They answer first to their clan and second to the government controlling the city they live in. While they have a reputation for violence and general nastiness, Rodians do not typically engage in organized fighting or wars, except in very dire circumstances.