The first plane to land was from the Ice Union, or, as most call it, the Glacial Union. They are a race of pseudo-humans who one day emerged from beneath the icy lands of Antarctica.
It was a pivotal moment for humanity, considering we had been living on Earth for centuries. Yet, nobody had detected an entirely different race of humans—or possibly aliens—hidden beneath the ice.
Their arrival was monumental and sparked a war.
They wanted to claim the Earth, but humanity wouldn't allow it. The battle lasted just seven days, but thousands perished. Ultimately, the Overlords intervened, and what followed occurred behind closed doors.
After that incident, the Ice Union integrated with humanity, eventually working alongside humans. Over time, the two sides moved past their hostilities and began forming families.