 Who are the Karna?
Somewhere out there, the ships of Earth were ranged against the ships of the alien Karna in the most important war that Mankind had yet fought. To violate the rigid social setup of Saarkkad would mean the instant closing off of the supply of biochemical products that the Saarkkadic laboratories produced from native plants and animals—products that were vitally necessary to Earth's war, and which could be duplicated nowhere else in the known universe. Not the worst ones, of course; there were places in the galaxy that were less important than Saarkkad to the war effort. "A special communication for you has been teletyped in from Earth.
 The Karna are the second most powerful race in the galaxy. They are skilled negotiators.
 The Karna are the second most powerful race in the galaxy. They are skilled negotiators.  The Karna are a race of warriors bent on destroying the Earth.  The Karna are a peaceful species trying to negotiate a surrender to Earth.  The Karna are a predator race who are trying to invade the Earth, to use humans as a food source.