The Grass-Eaters were, or are, said to be "men with no skin, and bright red hair".
They were a hostile and warlike tribe of the far forests who practiced cannibalism. They lived on a lake in a cave, on rafts made of plants, so they were safe from attack. After a long struggle a coalition of tribes trapped the remaining Grass-Eaters in their cave. When they refused to come out the tribes piled brush before the cave mouth and set it aflame. That was the end of the power of the Grass-Eaters, although some say that a few survive, and yet prey on the unwary.