Zana is a planet. It is not in the solar system. Whether its star system is in the same Milky Way Galaxy as the Solar System is unknown. The Zanans are peaceful people. There has not been any weapon on Zana for thousands of years.
In "The Lost Island", a group of Zanans are trapped on Earth. They have no immune defense against microorganisms causing diseases on Earth. They protect themselves with an impenetrable force field that also renders it invisible from a distance.