The Arbiter Republic was actively assembling their army and also contacting allies at the same time. The Aslan Empire had broken the rules first, and had completely inspired the aggression against the Arbiter Republic. The Arbiter Republic took the initiative to contact the Underworld as well. They didn't have much combat power, but they were good at destroying things. This was just a question of price.
Arbiter and the Underworld had their own plans for the future. The chaos in this world was very suitable for the people of the Underworld. They had a clearer idea now that the Milky Way Alliance was developing towards the direction of war. The era of the Underworld and pirates was coming.