Dawn Hunter

Dawn Hunters are a semi-mythological entity consisting of automated self-replicating war machines, supposedly responsible for the reduction or even annihilation of entire extraterrestrial civilizations in the Orion's Arm universe.

Etymology
Why they were labelled as hunters of the dawn is never explained. However, dawn might refer to either the distant past, when the galaxy was 'awakening' with intelligent life or the fact those hunters would have attacked any interstellar civilization that was on this dawn.

Nature
The mere existence of the Dawn Hunters is disputed. With that into account, nothing is known about how they look like or how they behave, except that they are autonomous self-replicating machines and they attack other extraterrestrial races.

Apart from the accounts of the Muuh civilization, who cannot be trusted due to their tendency of distorting even historical accounts for sensationalism's sake, hints of past nanoswarms are the only evidence supporting the existence of the Dawn Hunters. Even if such evidence showed that they did in fact exist, it would still not prove that they are still alive.

Legends
According to folklore in the Terragen Sphere, the Dawn Hunters were built tens of millions of years ago somewhere in the galactic core by unknown creators. Their original purpose was that of scouting the Milky Way to intercept any alien misbehavior according to their creators' point of view, as well as bringing protection from any possible nanotechnology akin to gray goo. However, another sinister purpose was that of eradicating any civilization that used the forementioned technology.

Supposedly, there were three groups of Dawn Hunters and each possessed a directive ruling a fraction of the Milky Way:
 * Platonic Directive - Ruled by the "logics", they favored the emergence of efficient super-intellengences such as Jupiter Brain megastructures. They destroyed any failed, inefficient culture.
 * Aesthetic Directive - Ruled by the "aesthetics", they valued complexity and protected naturally-evolved, life-harboring planets. They destroyed any culture that did not become more complex over time.
 * Enigma Directive - Ruled by the "enigmas", they were never understood by any species. One hypothesis suggests that they were "just a joke" made by their creators.