The Shivans are a sentinent species who probably come from an unexplored region of the galaxy. Two of the most devastating wars were fought against the Shivans: The Great War and the Second Shivan Incursion. Even though both Terran and Vasudan scientists experimented with Shivans, still not much is known about this species. There are many non-canon theories however including the very contraversial Shivan Manifesto and less well-known theories by various individuals such as ngtm1râ€™s Shivan Theory.
Shivans have multiple eyes, some of which seem to have the function of compound eyes, not unlike some varieties of insects. Shivans also have five legs, and can run equally well over a floor or over a ceiling. It has been hypothesized that Shivans may have spent their evolutionary process in a zero-gravity environment. Each Shivan leg ends in a very strong claw, capable of crushing even the sturdiest of known alloys. Parts of their thorax seem to act as compartments, such as ones that might be found on a space suit. It has been suggested that what we have actually seen have been either robots or organic creatures in some sort of exo-skeleton. However, we have, at present, no reason to support either hypothesis.
Their insect like carapace does not appear original to the creature's physiology, suggesting the Shivans are a cybernetic fusion of biology and technology. The integrated plasma weapon also exhibits properties of an organic artificial fusion. The weapon may be a kind of focusing device powered by the energy of the being itself, though this point is the subject of heated cotroversy. These details are cited as evidence that the Shivans could not have evolved as the Terran or Vasudan species had, but that they were likely constructed by another entity. Only a handful of Shivans have ever been captured, and all research on live specimens ended with the GTI's Hades Rebellion in 2336. The results of these studies remain highly classified.
Despite what information we've been able to obtain, Shivans still remain, on many levels, an enigma to both the Terrans and the Vasudans. Their origin and their destination remain unknown. While many have offered up possible explanations as to why the Shivans seem focused on the destruction of all other sentient species, we still do not know why they seem bent on total xenocide.
Though the Shivans are obviously xenocidal, their motives and origins have yet to be determined. According to Ancient artifacts, the Shivans seem to possess some kind of sensitivity to subspace disturbances. It is unknown why the Shivans returned to now-GTVA space in Freespace 1 and 2; it may have been by chance, cycle, or by the detection of Terra-Vasudan subspace travel and / or conflict.
One theory, suggested by Admiral Petrarch in the (player survives) end monologue of Freespace 2, is that the Shivans are a nomadic race cut off from home, much like the Terrans are from theirs. This theory goes on to speculate that the Shivans used the Capellan supernova to create some form of 'bridge' allowing travel to another (their home) universe.
Xenobiologists know very little about Shivan society. A leading hypothesis is the hive mind theory, arguing that Shivan society is broken down in specialized functions driven by a collective intelligence. The most convincing evidence supporting this theory is the behavior of Shivan forces following the destruction of the SD Lucifer, the turning point of The Great War. Other experts caution against attributing insectoid properties to the Shivans, regardless of their appearance and behavior. Shivan communication seems to occur through quantum waves; Admiral Aken Bosch's ETAK project was successful in decoding their transmissions, but all data concerning that project has been classified at the highest level.
However, due to the capture of the specifications of the ETAK project, it is possible that the GTVA may try to communicate with the Shivans at some point in the future, or possibly create a device to monitor and/or disrupt their communications. Either of these possibilities may hold the key to surviving a future Shivan incursion, as from the last two major encounters it is evident that the Shivans exponentially increase their power between campaigns against other beings.
Shivan technology has proven baffling for both Terran and Vasudan scientists. Although their weapons and technology by necessity obey the same physical laws, the systems of Shivan craft seem to be fully integrated with the pilot's biology, making it difficult (but still possible) to use their spacecraft for espionage. Additionally, reverse-engineering Shivan technology has led to tremendous advances in shielding, beam weaponry, and other weapon systems. Shivans seem to depend more on primary weapons than secondaries, evidenced by their bombers' low payload capacity. Shivans also rely on their heavy shielding and use little armor plating on their fighters.