The gusano (Vermes grandezii xenos) are a species of advanced aliens that seem to have originated deep in the galactic core. Historically disunited, the various gusano states banded together against what they (not so erroneously) believed to be a threat to their very existence: the human race. The gusano, while having incurred the wrath of humanity, have yet to be wiped out, mostly due to the distraction provided by the Galactic War. Collectively, they currently pose the greatest extraterrestrial threat to mankind, and are comparable in power to the weaker great powers.
The gusano were named by the famous Coalition Admiral Grandeza, who when presented with some gusano juveniles mentioned they looked like worms, or “gusanos” in Spanish, an old Terran dialect. Mature gusano look nothing like their young, instead resembling prawns and gorillas more than their maggot-like larva. It is known that most life the gusano have xenoformed their colonies with feed on nuclear reactors and gusano juveniles nurse around these reactors to gain energy from the heat before entering a pupal stage and becoming mature gusano. Because of this, gusano worlds are littered with artificial nuclear reactors, normally without any form of shielding as the gusano suffer no ill effects from radiation levels that would kill a human. This has made terraforming gusano worlds difficult, but not impossible, as thanks to the Collapse mankind has experience in reviving irradiated worlds. The gusano’s dependence on nuclear reactors has also made them target human ships and converting them into “nurseries.” The gusano are known to prefer hot, desert environments with carbon dioxide atmospheres.
Gusano technology is very advanced, the gusano apparently using the natural nuclear reactors available to them to advance much faster in the fields of electric generation and the assumed prevalence of heavier metals in their homeworld’s crust should have helped them with metallurgy. It is known that they have developed Alkaev drives much later than mankind at a comparable point in development. The gusano have yet to master coilgun technology and energy shielding, giving mankind an advantage over them in that regard.
For reasons as of yet unknown, the gusano prefer tripods to conventional armored vehicles, and sonic and EMSEL weaponry is more prevalent. The former has been exploited ruthlessly by the human militaries, which send small fireteams with antiarmor weaponry to shoot off the tripods’ legs, forcing even the most conservative gusano polities to adopt human designs. Suicide bombers are also common among the gusano militaries, but whether this is an act of desperation or some sort of religious fanaticism is still unknown. Gusano militaries also employ what could only be described as “jetpack infantry” armed with discus-like explosives and front-line infantry armed with melee weapons (usually made out of hard, irradiated crystal shards) have been encountered on more than one occasion.
Thanks to incompatible software, barely translatable languages and constant hostility between the two, humanity is not very knowledgeable about gusano history, politics or culture. What is known is that gusano unity is a recent development and caused by mankind’s excursions into gusano space and gusano studies on other xenos that mankind has exterminated or enslaved. It is known that the gusano as a whole have a more prominent warrior culture than mankind and several gusano “nations” are extremely xenophobic to the point of shunning any objects and practices of non-gusano origin, but the most successful groups tend to be the ones that embrace human technology and combat. The largest gusano group, the Sons of Mzha, is closer to a religion than a state, but from what little human xenobiologists know the distinction is blurry.
Observations on human attacks against some gusano worlds reveal heavily irradiated altars where gusano juveniles have seemingly been sacrificed (gutted and turned inside-out, with strange markings carved into their flesh) and mass graves filled with the corpses those physiologically unable to fight against the invading humans. Piracy is also very common, with gusano raiders boarding defenseless vessels, venting the atmosphere to kill any humans inside, and flying the ship into gusano space. Torture, both of human prisoners and other gusano, by some gusano polities is well-documented and has led to a no surrender policy among invading humans. Undoubtedly, these brutal practices are not universal among the gusano, just as dictatorship is not universal among mankind, but the frequency of these findings has steeled mankind’s hatred for this new foe.