Useful information regarding the Outsiders is difficult to come across. This help file will be split into three sections: a Timeline of events, Facts and Rumours.
TIMELINE
In late May of 2297, the League, AEU and Fringe pilot leagues, with the assistance of the EAOS, manage to locate and destroy the main fleet of the unregistered pilots calling themselves Renegades. After this, the survivors of the Renegades surrender, only for a massive unknown starship to emerge, revealing itself to be the source of the Renegade's superior technology.
This ship was the alliances' first sighting of an Outsider vessel.
It declared human independence over - from that moment on, humanity had been subjugated by the Outsiders, and a portion of all production from both the humans and Jinu is sent to Outsider space in unmanned transport starships. For the most part, the touch of the Outsiders on humanity during this period was relatively light. Non-pilots know very little of the situation, and even the pilots themselves see little in the way of evidence of subjugation. Over time, however, humanity's rebellious streak seems to give the Outsiders pause, and restriction after restriction are put in place.
In 2304, however, the Outsiders announced that the Terms of Occupation had been violated, and began their campaign of devastation. Once the beacons allowing humanity and the Jinu to locate one another were destroyed, all space stations, spaceports and centres of technology in human space were destroyed. Humanity was sent to the brink of civilisation collapse, and the Outsiders tightened their grip on the human race even further.
FACTS
Only one Outsider has ever been seen, and even then only by the respective leaders of the alliances and a handful of pilots. This was Zmnyaz, who appears to be the creature in control of the Zmnyi Myaz, what humanity has termed the Outsider Mothership.
The Outsiders are tall, seven-feet tall creatures. They possess cylindrical bodies supported by three long, thick legs spread out equally around its base. Three-quarters up the body are three tentacled limbs, and near the tip is a blue band that extends completely around the cylinder. Zmnyaz at least does not appear to wear coverings, but it did possess a device that translated its own method of communicating (some form of low rumbling) into human words.
Travel to or within Outsider-controlled space is banned, any alliance ship entering space not holding an active human beacon but claimed by the Outsiders is likely to be destroyed.
RUMOURS
The blue band at the tip of the Outsider's body is assumed to be its eye, meaning that they have full 360 degree vision.
Considering the actions of Zmnyaz the (very) few times it has met with alliance leaders and pilots directly, along with the extreme distaste the Outsiders seem to have for actually interacting with humanity, it is believed that the species is highly xenophobic.
The exact extent of Outsider space is unknown, but it is clear that it is vast even compared to the once combined Human-Jinu Known Space.
The Outsiders refer to humanity as Species #187, though whether this is merely a catalogue number of all species encountered or some other reference is unknown. Even this by itself, however, implies that the Outsiders know of, if they do not actively control or subjugate, many other alien species.
It is also implied that, due to how humanity and the Jinu first encountered what we know as the IFS, along with the unknown Battle Thralls that currently assault human space, that the Outsiders prefer to use vassal races to control others, rather than interacting directly themselves if they can avoid it.