New Kashubia Series by Leo Frankowski, Dave Grossman

He was a rugged, hardened combat veteran who had gone to hell and back -- in virtual reality! Now he had to face the real thing! The planet New Kashubia was rich in heavy metals, but its surface was baked with deadly radiation, so the colonists lived in tunnels drilled in a thousand foot thick layer of solid gold. Lacking carbon, oxygen, hydrogen, or even dirt, they were the poorest people in the universe... moreHe was a rugged, hardened combat veteran who had gone to hell and back -- in virtual reality! Now he had to face the real thing! The planet New Kashubia was rich in heavy metals, but its surface was baked with deadly radiation, so the colonists lived in tunnels drilled in a thousand foot thick layer of solid gold. Lacking carbon, oxygen, hydrogen, or even dirt, they were the poorest people in the universe. But when they combined virtual reality with tank warfare, giving their warriors a close symbiosis with their intelligent tanks, neither war nor the galaxy would ever be the same. Not to mention sex . . . less

New Kashubia was a planet rich in heavy metals, but utterly lacking in carbon, oxygen, and hydrogen. Even dirt had to be imported at great expense. The colonists, moved there from Earth against their will, lived in tunnels drilled through solid gold but still were the poorest people in the universe. Since their only resource was people, they sent draftees out as mercenaries, fighting in tanks in symbiosis with a highly intelligent computer... moreNew Kashubia was a planet rich in heavy metals, but utterly lacking in carbon, oxygen, and hydrogen. Even dirt had to be imported at great expense. The colonists, moved there from Earth against their will, lived in tunnels drilled through solid gold but still were the poorest people in the universe. Since their only resource was people, they sent draftees out as mercenaries, fighting in tanks in symbiosis with a highly intelligent computer. And Mickolai Derdowski had fought bravely and brilliantly for nearly a decade, losing many friends in the process, and risen to the rank of General-he thought. But then he found out that it was all in virtual reality. The war had been faked, no one had died, and he was still just a tank commander, not a general at all. But New Kashubia had been well paid by the planet that had hired the mercenaries for the war they had faked, severe food rationing back home was no longer necessary, and people could now afford luxuries like homes and clothing. There was just one problem. A real war was looming on the horizon and this one couldn't be settled in cyberspace. A lot of people might get really, permanently killed. Such as Mickolai. . . . less

First, the involuntary colonists of New Kashubia rescued their planet from crushing debt by becoming virtual reality mercenaries, then they successfully revolted against the oppressive government of Earth, but now they are menaced by the Mitchegal, a species whose biology has made them inherently evil. The carnivorous adults lay and abandon vast numbers of eggs, some of which grow into vegetarian juveniles, which are the adults' only food supply... moreFirst, the involuntary colonists of New Kashubia rescued their planet from crushing debt by becoming virtual reality mercenaries, then they successfully revolted against the oppressive government of Earth, but now they are menaced by the Mitchegal, a species whose biology has made them inherently evil. The carnivorous adults lay and abandon vast numbers of eggs, some of which grow into vegetarian juveniles, which are the adults' only food supply. Their culture has no family life, they eat only meat, have nothing like sex, and their main pleasures are gambling, art, and killing each other. They are an ancient civilization, millions of years old, with thousands of densely populated star systems in their realm. Lacking an immune system, they must completely sterilize any planet before they colonize it. The region of the galaxy they occupy is rapidly expanding...and Human Space is their next frontier! less