Jackson Gregory
Ru, the Conqueror
1933
from the dustjacket:

If you enjoy the Tarzan books or thrill to yarns of brave deeds here is a story for you. It is the eventful tale of Ru who came to be called Ru Broad Ax; who as a boy fled his people, the Valley Dwellers, rather than serve as a sacrifice to the Gods of the True Harvest; who became the greatest Wanderer of his time, met and won the lovely Dawn Maiden and in the appointed end returned to conclude matters with Urg, the Witch Man, and to lead his people out of a great danger and into safety and a new life.

The records of these happenings are inscribed enduringly in many places and in many ways, in the stones themselves, in an ancient ax-head and a handful of arrows and a flint knife, in shreds of pottery and even in fragments of linen and baskets, and in pictures drawn more than ten thousand years ago on the walls of dark caves. Both as a stirring, swiftly moving tale of adventure and romance and as a faithful reconstruction of life in the misty ages before history Mr. Gregory's novel is engrossing reading.