Ravagers are a race originating million years before Protheans founded the Citadel. From a small race which controlled the galaxy they grew into an empire. This empire was ruled by only one emperor. Ravagers hated to use Mass Relays so they created their own technology. Max Tubes, or otherwise known as Mass Tunnels. This technology could link two locations in the galaxy and created tunnels between this two points. They later discovered a gigantic force and migrated just before the Reapers invaded. The lived in a galaxy far, far away, but the galaxy has been dragged into a giant black hole. After this they returned to their home galaxy. This led to an interstellar war with Citadel council, batarians and Terminus fleet.
Entirely covered under bullet proof skin they are as powerful as 4 krogan warlords. Able to breath air and underwater they are nearly undestrucible. Because of their homeworld being a terrible place where no one could have survived if they didn’t terraform it when they had to genetically change their eye sight to a state at which they see at day with normal eye sight and at night they use night vision.
Their government is a lot different. They have one emperor who rules over all their systems. His word is more than just a law, it is an objective for life that should be done. If it is never completed they will end their live with a suicide.
Ravagers have the best ships ever created and their technology stands above everyone else. Their marines do not use any armor because their skin is bullet-proof. They have one type of a weapon they always have with them which is Biotic Rifle which aims biotic pulses which can destroy anything. Their ships are even better which cant be destroyed. But their weakest spot is their recharging technology which refill the strength of their weapons. During this period their vulnerable. Epsilon Projects later created a virus which slows down the time of recharging. But undefeatable marines would still be a problem. But then their skinned can be destroyed by firing Quantum charged bullets.
Their main Military force is Galactic Fleet which has more than 1,000,000 units in it. The of this fleet is unknown but it is known that it can be defeated because during Battle of Astayx they were defeated which led to a number of victories from Citadel Council side.