Void Raiders

Pirate faction of the Arcturus galaxy. It was founded by a large group of most Arcturus native races, thus, it has no main species.
  Although they raid primarily defenceless civilian starships, the Void Raiders will modify them with improvised weapons. 
  They will almost always enslave anyone captured, taking everything that person has. As slaves have proven very useful to the pirates, they prioritise trying to keep the people in the ship alive. 
  This is done by immobilizing the ship by shooting it in the engines and weapons, if any.
  Because they are poorly equipped, the raiders need to be very careful around those ships escorts, especially dedicated military ships which sometimes take up the role of piracy suppression. The pirates often need to deploy probes to scout because the possibility that a military ship would be nearby - especially considering the largely superior radar of their enemy - is far too great to ignore. 
  However, they have become very used to the areas of space they patrol as well as all civilian traffic. They can predict in many cases where a fleet will end up after several minutes and avoiding police and military forces.
  Furthermore, many star nations of Arcturus largely ignore the pirates as a threat because of sheer arrogance. As such, despite their poorly equipped nature, the void raiders is still a powerful, galaxy wide, piracy organised crime organisation.
  They particularly like stealing enemy technology. Anything advanced enough can help massively reduce the technological edge. The pirates can very easily detect starships of the Hyperion Federation due to the massive energy signature. The pirates have learned to avoid HF ships as they can detect ships from superluminal distances unlike any other civilization in the galaxy.
  How the Void Raiders treats any slaves they capture significantly depends on the leaders who capture them. Some leaders treat them well as they might realise that they can work better with high morale or, very rarely, because they feel bad for the slaves. Many pirates, however, will treat them horribly or in rare cases might kill them to eat them during important feasts. In Void Raider culture, there are very few stereotypes against masters who treat slaves well or poorly, so any slaves captured would have a roughly even chance of ending up under either group.
  While the Void Raiders have pirate bases in various random locations around Arcturus, they are not totally dependent on them. They are highly mobile, and as long as they have resources their ships can continue indefinitely through the void of space. Sufficient resources may be obtained by salvaging other ships, or perhaps by fabricating them in large mobile factories.
  The Void Raiders aim to invoke fear into their enemies, often by swarming them with large numbers of ships with high fire rate, painting their ships black with various death-related symbols in many locations as well as well placed red, glowing lights which can scare most species. Sudden ambushes are a favourite strategy of the Void Raiders, sometimes seen hiding behind asteroids or even disguised as asteroids. The overwhelming numbers disparity in such situations is also known to heavily damage the morale of most species.