Gordon R Dickson 
Lost Dorsai [EPUB ebook] 
The Childe Cycle Book 6

Renowned throughout the galaxy as the finest soldiers ever born, the men of the Dorsai had been hired by El Conde, sovereign of Gebal Nahar, to transform his rag-tag army into a fighting force to be reckoned with.Now the revolution had erupted, and the men once trained by the Dorsai bore arms against them.Bound by their rigid code of honour, the mercenaries’ first duty was to protect El Conde from the rebels. But what chance had a handful of warriors, however noble and fearless, against the massed ranks of the Naharese?