Planet Earth.
Alexander swiftly went back home after creating the Universal Accord Commission. He didn't really care much about what the Council members were thinking. He had tried to stop its progression, but humans were complicated.
Despite the dangers still in the universe, people felt safe. The threat of void creatures could only be found outside the borders of the Empire. And there were dedicated hunters out there cleaning up those monsters if they even got close.
So the question was: why not?
Why not expand from the confined spaces they found themselves in? Why not become as free as they possibly can? Why not claim the vast resources the universe had to offer? They had a dedicated guardian watching over them; the limit was only their imagination.
Those with power could no longer sit back and watch only a few people rule over everything. As such, plans were born, alliances and deals were made, and initiatives were taken.
