In game, the final space-type, Dead Space (by-default) is viewed as the green regions of space. These regions spawn celestial bodies of only one biome type - Corrupted. This region can spawn the highest level of celestial bodies, up to level 9! The planets which spawn in this region can also be upgraded 5 times (the most of any space-type, along with Deep Space).
The colouration of the background where Dead Space is the Space-Type (fancy-shaders on)
A peek at a Corrupted Planet within Dead Space - Corrupted is the only biome which spawns here!
It is likely that Dead Space will be the final space-type you both discover and reach within the game - it borders only Deep Space. Within a round, there will often be several celestial bodies which you capture in this region, however, due to the extremely low defense, only x0.15 that of Nebula, it can be difficult to hold on to these bodies - the region helps to provide points of contention for empires. The bonus is that celestial bodies within Dead Space have double the same-level values of Nebula, 66% more than Space, and 33% higher Deep Space, making them incredibly powerful, assuming you can keep control of them!
This region also has some of the highest efficiency stat artifacts, which all boost 4 or more of the stats of a celestial body (other regions only boost 2-3). They also spawn twice as many foundries for most levels, at the cost of reduced planet spawns, making in easier to amass a large collection of these powerful items to spread across your empires most powerful celestial bodies.