The Nostluhk are one of the older races in the galaxy, once a nighty power they are now a shadow of their former greatness. They rule over the Nostluhk Dominion, which was once the major power in the galaxy, but over the last 1,000-years has fallen from power and shrunk to just a few systems. Nevertheless they are still seen as one the major powers in the galaxy, mainly because of their enormous and advanced starships and their refusual to negotiate. They do what they want, when they want, and anyone who tries to stop them is destroyed.
One of the things that has caused their downfall in a vicious plague which has destroyed 99.9% of their popualtion and is slowly killing the rest, Usually a long lived people, living 500-years or more, they have been attacked by a virus encoded to their DNA which gradually eats them alive. Those who have survived are little more than walking zombies, kept alive with respirators and body suits, and closing healthy organs and replacing them as and when needed. Over the top of this they usually wear a large hooded cloak.
Much of their power is now spent on trying to find a cure for the plague that is killing them.
The Nostluhk have not been defeated in battle in living memory, add that to the fact that they do not negotiate makes them a terrifying adverasry, which is why everyone gives them a wide bearth.