Before the factions of Earth declared war on one another, they would arm and pay mercenaries to attack their rivals. This practice continued through most of the war. When the colonies declared independence, these mercenary ships signed on to be the defensive fleets of their home colony.
Although pitted against each other, there were many more Earth ships than mercenaries. Instead of a straightforward approach, the defense fleets would goad them into fighting with one another and swoop in as the battle neared its end. A favored tactic was to attack Earth ships and warp out quickly. Then, another ship would show up to assist. Once inside, they would kill or capture the crew and take the ship for themselves.
Earth corporations did not get the hint when faction fleets were driven off and refused to relinquish their holdings in the colonies. The companies which refused to pay for the land they occupied had their holdings in the colonies seized by the local management. They took over operations and became independent, using all of the company’s assets for themselves. When ships were sent to reclaim their holdings, they would be attacked.
Only the Independent faction was left alone, for all their aid to the colonies through the years. As such, Independent faction ships are not as common in the colonies as Alliance and Federation ships. Companies originating from nations in the Independent faction are also more abundant in the colonies, as they were the only ones met with open arms and cooperation.
After the war, many veterans left Earth in droves. Because of the formation of the UEG, they were not cared for like they were supposed to be. Many injuries went unattended and the veterans struggled to find work. As a sign of solidarity and in protest of the poor treatment of his former soldiers, Nikolai Markov, renowned former general of the Russian Spaceforce, publicly left Earth alongside other veterans. During deweaponization, some embittered vets stole a decommissioned ship out from under the UEG. After the first time, it became a problem.
The UEG never changed its policies, and soon there were few veterans left who were ranked Gamma or below, as Alphas and Betas received preferential treatment in all matters. Many of those who were left joined groups of people moving to unpopulated areas to establish new towns. Older veterans took in whoever they could and helped them find stability.
Around the Earth and throughout the colonies, veterans who had sacrificed and risked their lives for nations that no longer existed were at least there for one another.
The UEG calls them pirates.