The "Great Evil"

The "Great Evil" is an alien race that was created by unknown origins. They have no actual language, and consist of mostly.. Unknown species, to begin with. They are made completely of Biomass, bones, and organs of the dead. These "necromorphic beings" are great threat to most races.

Origins
While their actual origin is unknown, first contact with these creatures was made about 500 years ago on one of Andrusa VII's moons. Every rescue party and military operation there has ended with all casualties, and no one has returned since those missions. It leads to believe they were all converted.

Converting process/Creation/Infection
There are three ways of infection. The first, and most brutal, being direct contact with a being itself. The most presentable way of this, would be a Slenderform. Slenderforms, when discompacted, are mostly heads. The head will latch onto a host body, decapitate it, then connect its own nerves to the host's spinal cord, taking control. Other ways are through Moosesharks, which will stab four tendrils into the host's neck and inject a parasitic biomass into the bloodstream, taking control of there nervous system via the cerebrum.

The second would be through sight of a Marker, an alien object that was analyized to spread the infection via imprinting the codes into the host's optical nerve, and into the brain, where the code would grow into a parasite, and take control of the entire brain.

The third way of infection is suicide within the vicinity of these creatures. The creatures will be drawn to any dead body within 1000 miles, and will consume and infect it at the best of their ability. This causes most of the races to either cower in fear, or burn the bodies.

Other information
While there is no identified weakpoint, arms and legs do nicely. They are invulnerable to fire and nuclear radiation, and are extremely versatile to all weapons, including Antimatter. These beings show no weakness to anything, and not even decapitation can kill these beings in one shot. Sheer force is not recommended, as it will only attract more of these necromorphic beings.