Five races of Aesca, the first five. Nuwep religion ties a race to a stream, so there are five races for the five rivers, and three races for the three fish, and two races for the two poison snakes. These associations are Nuwep association, and may not be shared by other races or even among other humans.
The violet river for humans, the race of humor, magic, and power. Humans are in ascendance during this, their fourth age, and the turn of the wheel will put the next race in charge of the world, while humans take up the backseat. For now, though, they are the most numerous, the most powerful, and while their history on the planet spans perhaps only a hundred thousand years, they have erected great cities that will stand for many more to come.
The red river flows beneath the golems, whom the Nuwep believe will eventually inherit the earth. They will live forever, and their ages will span millenia. Created by humans in their power, golems can now self-propagate using factories or even good-old-fashioned engineering knowhow.
The yellow river touches the narhoojai, also known as the Secret Race and the Shapeshifting Reptiles. They have lost their original form, and have persisted in some shape or another for over ninety million years. They know many secrets about the world underground and only come up to impart wisdom or chase after their most prized drink: milk.
Sky-people live with the white river, and are Thunder's children, and fly in the skies in glowing balls of light or red cigar-shapes, or even liquid spheres, walk among hallways of some liquid-seeming metal, and dwell in the sky on the edges of the places where the world-dreaming is still weak, and the powers that forge the world still churn. They can be visited by and visit only those who are half awake themselves, from drink, drug, or fatigue. Those who entreat with them lose many of their memories of their time with them, but it is always pleasant, sharing stories, sharing food, and being shown the light that roils in their head.
The blue river touches the opanian, who dwell deep in the sea and never touch foot on the surface except to impart their own secrets. They are recent to the world, and it is truly alien to them. They are also their technology, and it is often difficult to tell where their magic, the sea, or their bodies begin. Even so, the world-machine has taken them to itself, and they are just as welcome as any to her fronds.