The Zarethians found some survivors though the city was in ruin. They took them under their wing and began to build on the planet. Military structures first, then prefabricated shelters. Soon there were many factories, houses, political buildings and shield defenses on the planet. It was now Zarethian as were its citizens. They had the choice of either becoming Zarethian citizens where they would recieve the freedoms there of or they could leave to a pocket dimension to start their own government again.
The Zarethians provided for the people they found and buried those that were dead. They were kind people they did want to help. They werent in it sorely for imperialistic gain.
The people would be able to keep their homes. Their businesses would be given a helping hand. They would be able to keep their life as close to the same as before except there is no totalitorian government. Some would accept help from the aliens, after what they saw, others may not. Those might stay to incite rebellion or just mutter around, arguing about it.