The Tratias Ru are a type II species of floater organisms that holds control of around fifty star systems within the Eros Star Cluster, inside the Dryas Cloud, region of the Ambrosia Galaxy.
Overview
Their main form of FTL propulsion is using exotic matter that has negative mass to reverse time dilation, thus making trips extremely quick, much quicker than with alcubierre drives and wormhole drives. These drives are known as Mass Dilation Drives to the Tratias Ru and many species within the Ambrosia Galaxy. However, the Tratias Ru don't have much motive to explore beyond their local cluster of stars.
Seeing building a Matrioshka Brain and transferring their entire population into a sandbox simulation as their ultimate goal, as opposed to the Humans' idea of expanding as far into space as possible, the Tratias Ru have never left their local star cluster. Because of this, the Tratias Ru have dedicated a lot of time to improving computation technology, going so far as to let AIs control their entire defence army. So far they've gained the ability to simulate many thousands of brains in a single simulation and alter them to control a robotic mech as opposed to a biological body, but they're not done yet. The Tratias Ru want to experiment with scanning themselves and being downloaded into a simulation.
The Ru-Public is fairly relax, having no desires and thus no need for money, meaning they don't need to replace their current system of trading unneeded necessities. This means that, despite producing lots of greenhouse gases, they have not altered many ecosystems beyond repair. However, because of their goal, they don't pay much regards to things that aren't in their territory.
Being extremely territorial, the Tratias Ru have never let their technology be seen by any other species, including the Humans and the Zythyns. The Confederacy of Borealis does not take this secrecy well, often demanding that the Tratias Ru hand over their technology to be used by species more worthy of their drives, although the Tratias Ru have not given in, afraid that everyone is against their idea of building a Matrioshka brain.
MDD
The main form of propulsion used by the Tratias Ru, Mass Dilation Drives reverse time dilation using exotic matter of negative mass to make trips around the cosmos thousands of times faster than Alcubierre drives and thousands of times easier than wormhole drives.
A Tratias Ru spacecraft with an MDD can do around 1000ly/s, going between the Via Sagittaria Galaxy and the Aylothn Galaxy in about 5 and a half hours, much better than the 2,000 years that Human Alcubierre drives would have to endure. These properties make them an ideal drive for expanding species such as the Humans to use. However, because the Tratias Ru don't want to expand but rather upload every Tratias Ru to a simulation, and because the Tratias Ru are especially hesitant to let anyone else know about MDDs, no-one else has been able to use an MDD for themselves. Using MDDs in everyday travel has become a pipe dream to many advanced species within the Ambrosia Galaxy.