Broos are one of the most common and most reviled creatures of Chaos. They are the proud children of the goddess Thed, who became corrupted by Chaos and joined with Ragnalar and Malia to become the Unholy Trio. They opened the world to Chaos, and now there are many Chaotic gods and monsters.

Broos are feared for their disgusting ability to impregnate any animal (or even plants or minerals, in rare and horrifying cases). The typical broo stock is based on whatever hardy wild animals are most common in the area, or livestock if humans live nearby. For example, the broos of Dragon Pass resemble cows, pigs and sheep, for these are the animals the Orlanthi prefer to farm.

In other parts of the world, very wild and dangerous broo variants exist, such as the rhinocerous broos of Prax. Broos based on predatory animals are possible but thankfully tend to be much rarer. A mad hermit in the Elder Wilds claimed to have seen an allosaurus broo, but this horror was never confirmed. Regardless of origin, all broos are larger, stronger and more resistant to pain and disease than humans, and many of them develop unique mutations, e.g. extra limbs or acidic blood.

Broo culture – such as it is – comes in two forms. The Feral culture is extremely primitive and structured around the broo lifecycle. Alone or in gangs, Feral broos will raid farms and mate with the livestock. Weeks later, any infected animals will give birth to dozens or even hundreds of slimy infant broos. They will try to escape to the wilderness, and any that survive will form a new pack of Feral broos. They know little magic, maintain little contact with other Chaos creatures and use simple weapons if any.

The other type of culture is called the Wild culture, and is both more advanced and more dangerous. Broos in a Wild culture live in structured tribes with leaders and shamans. They may have contact with other Chaos creatures like ogres or scorpion-men. They will conduct coordinated raids and will have battle magic at their disposal. They may even be able to obtain or manufacture proper weapons and armour.

Broos are hated by all living things and killed on sight. However, broos aren’t inherently evil, and some are able to rise above their vile kin. The Wild Healer of the Rockwood Mountains is a broo healer and a cultist of Chalana Arroy, and he has healed countless people though he is still hunted when sighted. Some civilised broos are citizens of the Lunar Empire, which has enough of them to field an entire regiment of the creatures. (source)