from the
wiki:
Centaurians are a light species, but this does not reflect in their personalities like the Terrellians. They are noble and loyal to their Empire. They are not as patient as Terrellians, but they are good at exercising it. Terrellians ride them into battle, and they can combine their light strength.
Memeruke (Rukes) were originally Centaurians. A convoy had crashed on Earth and those born there fell from light. They are greater in size and strength than the Centaurian brothers. They have a hypersensitivity to touch and sound making them more agressive.
Rukes have a male dominant gene and 4 out of five foals born to them are male. So they have to take wives from Centauria. They tend to be abussive as they are sensitive to nagging. Half-bloods (Centaurian mother/Ruke father) have a 15% chance of being born with light, which makes them calmer.
They are nomadic raiders. Living in advanced tents because they have in the past been attacked or having entire clans obliterated. They raid for survival purposes, and have recently taken up taking captives to sell as slaves to bring a higher income.
They are extrememly territorial, avoid their colonies and camps. The tribe has been shifted in the Balances of power since the last Ruke war.