I really liked Dan Worth's Progenitor trilogy. It starts off a tad slow but becomes insanely epic as it goes.
''Katherine O'Reilly and Rekkid Cor. Human and Arkari. Archaeologists with a story about an ancient derelict starship that few believe and a captain's log that tells of an ancient genocidal war that no-one has ever heard of. But if no-one believes their story, then why are the authorities so keen to suppress it? Captain Michelle Chen of the Commonwealth Navy. Brave, cunning, merciless. Dangerous even. However she may be just the person her superiors have been looking for to start a war. Steven Harris. Secret agent with a conscience, who defied orders, ignored the chain of command and let his morals get in the way of his career. Quickchild. An AI of unknown origin and staggering power.
As the colonies of the human Commonwealth stand on the brink of war with the fanatic legions of the alien K'Soth Empire, these five individuals are drawn to the backward, arid planet of Maranos that stands between the two civilisations. As relations between human and alien deteriorate, Maranos is about to give up its ancient, terrifying secrets.''