Swarm

The swarm is a large pack of small creatures living in the clouds and attacking any source of Electromagnetic turbulence, like radio emetters, WIFI, heat guidance system, X-ray, nuclear fission etc.

They come directly from the Leto and are the main cause of the difficulty of rebuilding technology and communications in the universe of no-return.

When they detect an electromagnetic turbulence, they attack by thousands, ripping everything in the area. They are sometimes "summoned" in terrorist attacks when it comes to whipe several buildings out.

It is believed that they come to the world as spores, getting "puked out" by Leto bulbs. When they come across water concentration like clouds, they stagnate in and grow into larvas, then into a swarm. The reason why they attack electromagnetic variations sources is actually unknown. They rarely can be found underwater, which consolidates the theory about the active principle of the water on the spores.

They are too small and fast to be individually killed. Some cities have D.C.A. on their roofs to kill most of them before an attack occurs, but it is virtually impossible to kill a whole swarm.

They can't be found in the regular sky, being incapable of living without a water environment.