The Contingency is Rapidly proving itself to be rather annoying to deal with as of late, a file on my desk by tomorrow.
History
What we know as the Contingency is actually a combination of several smaller forces that have been lumped together under the influence of the Reaper's virus.
The Geth: The Quarian's rogue linked VI programs and old enemies who chased them from their own homeworld for their own safety following the Council's shut down ultimatum.
Custodians: The Tebrid's own servitor forces, and until their unwilling defection the back bone of the Tebrid's civilisation.
Valhalla Industries: A Collection of Various synths and uploaded consciousnesses bounded together by little more than their collective criminal records and the Union's need for disposable forces in the face of the various horrors to come out beyond the Galactic border.
The individual histories of the three organisations until the Reaper's attempt to invade has already been covered. After the Reaper's invasion the various scrapped remains of the Reaper's technology began to transmit across the Terminus system, a variant of their indoctrination signal we assumed, up until the machines went on the offensive. Near as we can tell, the signal contained a virus that broadcast the Reaper's ideals across the entire sector and ingrained them into all of the AI systems in the sector. The end result of this has become the core tenant of the Contingency's beliefs and operations: The extermination of all organic life in the galaxy, because according to the Reaper's organics and synthetics cannot co-exist, with the original uncorrupted programs working to purge themselves of this madness.
An attempt by now deceased Admiral Daro Xen of the Quarians saw this situation greatly exacerbated, a data compression program that gave both sides the power to build fortresses in the digital landscape of the collective of the Galaxy's Synthetic hardware platforms. While they've been fighting us in real space they've been fighting each other in cyber space. Then the buggers started to manipulate time and space. We believe they got their hands on one of the Lithoid's shipments of Neu Eezo, or a Turian lab that was experimenting on the stuff. They created a massive Anti-gravity well in the core of their territory, which they used to accelerate the flow of time around themselves, and then coupled that with building several matter decompressors to fuel their own operations. Through a combination of this process we believe they've resolved their civil war, there is nothing left but the Reaper's Contingency. Currently the biggest threat represented by the Contingency comes from the System Killer weapons, the Sterilisation hubs.
Military
The Contingency regularly sends raids out into the Terminus system consisting of various ships with Hulls of Neutron Density Carbon Cubrate, or Silaris ship plating as the Asari are so fond of calling their little brain child. Essentially the ships becomes locked on a molecular level, and under the influence of the massive white Hole that sits at the centre of the territory the ships 'surf' on the wave of anti-gravity towards council space. Aside from that Contingency weapons is a hodgepodge of AI guided missiles, nanite flak guns and Mass Effect based shield generators, which also serves to lock the ships on a molecular level and reinforces their integrity. The most prominent feature of the Contingency is their Sterilisation hubs.
These massive ship worlds, powered by the still beating hearts of the Reapers, serve as the ultimate weapon in the Contingency's arsenal. These moon sized ships are simultaneously Colossi, Mining facilities, factories and fully mobile ships. Each of them are designed to destroy worlds, chew through the debris, refine them and build parts for new warships all for the purpose of rendering all biological life in the galaxy extinct. But it's not enough that the Contingency has the biggest and baddest weapons in the galaxy, they also have some of the best infiltrators too. They've been dubbed Terminators, robotic infiltrator units made in the image of the various sapient races of the galaxy.
The Terminators feature a ultra-realistic layer of skin made in the likeness of any race they deem that they need, The disguise goes beyond the surface though, each Terminator is engineered to match the exact biometrics of the people that they're based on including their organs. That said each individual Terminator is also far stronger and have much higher stamina than their biological counterparts do, even if their original counterparts knew nothing of such things each Terminator is extremely knowledgeable in the use of martial arts suitable to their race and has been programmed in the use of fire arms. As soon as a Terminator has been identified it must be put down with extreme prejudice, preferably without alerting them that you are aware of their existence.
There are two methods of detecting Terminators in wide scale use, the first is to have a psychic attempt to read their minds. Being machines the Terminators do not have anything that can be read, conversely when their thoughts come up empty then they are exposed. As the council has few and far between with psychics they've instead resorted to the so-called 'cut test.' At every entry point of major citadel centers guards have been stationed with the specific job of drawing incoming residents and visitors blood from various different parts of the body. Several Terminators have been caught with this method, though after a while they started to slip by after filling the gaps inside their bodies with blood taken from their victims, so now the blood testers also make sure that it's fresh and it actually belongs to the person it came from.