Keeper

The Keeper is a "Sub Boss" enemy that contains the Swarm, there is actually 2 of this enemy in every given galaxy. It will appear in the galaxy at the end of 2 blue lines that will be targeting the swarm sector.

The Keeper is a really fast enemy that will try to use its laser to damage your ship, while trying to stay around 2 KM from you, so you will need a really powerful Thruster to try going behind it. The main laser may be the strongest weapon (and be aware that it can slightly tilt the laser to try to hit you), but it does have 3 Railguns that shouldn't be much of a problem. Its important to note that trying to destroy its engines is not easy, since it has 60 health on them and repairs quite fast, but it uses a C.C.G. Hull - Military Grade, so it doesn't have much health.

On defeat it will drop 2 scrap (which could drop a railgun, the core, etc.) but don't think the keeper will drop a Keeper Beam. Both Keepers must be destroyed to free and battle the swarm