Screamers

Screamers are one of the least known species in the known Galaxy - and the absolutely greatest potential threat. They were narrowly contained during the Settlement-24 Incident. Even the most conservative estimates of the outcome of Screamers breaching this containment include trillions of civilian casualties and possible destruction of Confederation of Mankind, Successor Codes and Insectoid Executive. The reason for that is simple - Screamers are the only known post-Wall of Faith civilization that still exists (with only the sidhe rivalling them on some fields). And what's worse, they are hostile.

Basic Information

Anatomy

Screamers are neither organic nor robotic or synthethic entities. Instead, they are believed to be the only telepathic lifeforms known to Mankind. They lack physical bodies, and instead exist as a complex, and self-replicating mental construct. There is at least five different 'patterns' of bodies that the screamers are presently inhabiting, at least according to the surviving data from the Settlement-24 Incident. It is believed that this bodies belong not to screamers themselves, and are either genesculpted bioforms created to be inhabited by new screamers, or members of species taken over by screamers in the past.

Genetics and Reproduction

Screamers are mental parasites that reproduce by infecting sapient lifeforms via a form of very powerful telepathy. Their mere presence immediately begins to exert their influence on every sapient organic creature within a ten kilometer radius, altering their brainwaves to form a new screamer. This process is typically 'felt' like a faint (but getting louder) 'scream' that seems to be coming from all directions at once (which is the source of the name of this 'species'). Once the process is completed, nothing remains of the victim's mind, which is entirely devoured by a newly born screamer. That possesses access to both memory of the former owner of his body, but also an expansive 'library' of genetic knowledge inherited from his 'parent'.
This effect can be temporarily suppressed if the attacked target has a particularly strong willpower, but it will be only temporary. What's worse, machines aren't fully safe from this effect. In their case its effects manifest as powerful viruses that overwhelm them in short order (unless a full AI is onboard, which is rare and, to be honest, it's only a hypothesis that wasn't tested thus far), leading to self-destructive 'behaviour'.

Additional Information

Perception and Sensory Capabilities

They possess all senses that their biological form has, plus a powerful parapsychic detection ability that allows them to detect (and infect) lifeforms within at least ten kilometer radius.

Civilization and Culture

Average Technological Level

Screamers have reached the level of a post-Wall of Faith civilization. This means that the screamer tech surpasses all achievements of the Mankind's scientists so much, that they can't even begin trying to decipher how it works. Every bit of technology they use is de fact class 2 to 4 xenotech, impossible to be replicated by any pre-WoF civilization. Of course, just as every post-WoF civilization, there are fields on which they seem to specialize.
The best description of their technological superiority is that during the Settlement-24 Incident it took twenty-seven capital ships to destroy two screamers ships of similar size - and seventeen of those capital ships were destroyed. The screamer incursion was only stopped by a deployment of spatial distortion generator which destabilized the hyperlane, preventing the screamers from calling in reinforcements. Engagement with screamer ships without possession of fleet-killing superweapons or twenty to one numerical superiority is highly inadvisable.
Screamers seemed to the especially interested in technologies that can be summed as anomalist-derived, such as telepathy, telekinesis and technopathy. Their specialization are cognitohazards and memetic warfare, however. Every screamer city is covered in cognitohazardous patterns that can 'infect' observers (even those seeing it through a camera feed, or a picture) with more screamers, or cause dozen different mental effects. Their ships typically carry similar patterns on their hulls, and even their missile salvoes were arranged in a highly complicated pattern that made human tactical officers and captains lose consciousness or vomit.

History

Very little is known about the screamers' past. Their empire used to be much bigger, but they lost a series of devastating wars (sometimes summed up as War of Screams or, less optimistically, as 1st. Screamer War) against the Aurum Imperium. It resulted in majority of their past space empire annexed by the Imperium, local screamer population thoroughly exterminated. Aurums also 'sealed' the hyperlanes leading to the core sectors of the screamer empire with (what is believed) some unknown spatial distortion type of archeotech.
This made the hyperlanes untraversable for centuries. It also redirected their screamer-side entrances from the interior of the solar systems to the void beneath the stars. Because of that, the chance to actually find them were close to none, even if the screamers looked for them - but they didn't. This is suspected to have changed in the aftermath of the Settlement-24 Incident, as now Screamers are aware of the fact that the hyperlanes are passable again and that they relocated.
The actual size of the screamer territories is unknown. Lack of outward facing hyperlanes forced them to expand their three sectors quite far. The estimates of screamer empire range from a hundred Garden Worlds to ten thousand.