The Silence
This Article contains spoilers for The Null War
The Silence is the name given to the extra-dimensional being that we know as nullspace. It is an O8 intellect and exists in every universe in all time as the same being. It is intelligent and hostile, actively trying to breach into our reality for unknown reasons. The Silence was temporarily pushed back into nullspace after The Silent War (The Null War). The Silence spreads in reality at the speed of light, requiring FTL capable ships to contain it.
Speculation
As it is impossible to fully observe and understand The Silence, most of this information is speculation gathered from other high OI individuals and compiled into a comprehensive list.
The Imprisonment Theory
The leading theory on the existence and nature of The Silence is that it was imprisoned in the form we know as nullspace to prevent it from manifesting in reality. Nullspace, while observed to be empty, may contain particles that are infinitely apart from each other. These particles may be the true form of The Silence, and a breach into reality may allow it to re-form into a cohesive being.
This form of imprisonment would require technology far beyond our comprehension as it would require the ability to create dimensions as well as generate infinite negative pressure. A civilization or intellect capable of doing this should be readily visible from the amount of energy required, but no such entity has been observed. This entity may also exist above our plane of understanding. An O8 or O9 level intellect may be able to perceive it.
The Anti-Existence Theory
Another popular theory is the Anti-Existence Theory, which speculates that nullspace is the antithesis to our known reality, similar to how antimatter is the antithesis to matter. This theory is based on original nullspace research where scientists expected to find antimatter on the other side of tears in spacetime. Instead of finding antimatter, they found nothing at all.
Under this theory, what we observe to be The Silence is actually that reality's intelligent beings. We cannot perceive them and they likely cannot perceive us. To them, linelayers tearing through nullspace and building Krasnikov Tubes may be the same as The Silence tearing through our reality and attempting to spread outwards. Essentially, we may be their version of The Silence.
Interactions
The Silence, while unobservable, interacts with certain forms of energy and technologies.
During The Silent War, almost every dyson sphere/swarm capable of firing in a beam configuration focused all of their firepower on the initial breach point of The Silence. The huge amounts of focused solar energy halted the advance of nullspace into our reality temporarily as the galaxy's OIs attempted to figure out a solution.
The Silence was vulnerable to high energy weapons such as particle beams, antimatter bombs, and high energy lasers. When tendrils of The Silence escaped through cracks in the dyson beam bombardment, fleets were sent to engage and dismember them at their weakest points. When detached from the main rip in reality, the tendrils quickly dissipated.
The Silence was eventually forced back into nullspace via a massive spherical array of null anchors. The event horizon generated by null anchors is capable of containing and transporting The Silence back into nullspace. The Silence actively avoids null anchors, gates, and black holes.
Reality Breach
The time in between breaches to our reality seems proportional to how many nullspace technologies are in active use. The more gates, skip drives, and siphons active, the quicker The Silence can breach into our reality again. The breach point can be determined by a sudden spike in Null Syndrome, gate instability, and null collapses.
The next breach is expected to occur within the next 600-2000 years.
It is unknown if The Silence has breached in any other parts of our universe.