Artem was one of the moons of Solterra. But, within this moon lived a race of humans that were referred to as Moon People.
Ironically, the other moon, which went by the name Chandrea, also had Moon People in it.
But, these two races didn't get along.
Countless wars had been fought between them in the past, but after a great struggle, the people of Artem won, forcing the people of Chandrea to go into hiding.
But, the Royal Family of Chandrea didn't run and hide, which was part of the agreement they had with the Royal Family of Artem, so that their people would be spared.
And, a year after that war, a girl was born between the Princess of the Chandrea, and the King of Artem.
However, this child wasn't born out of love.
No.
She was born so that the King of Artem could absorb and refine her bloodline, allowing him to become a Celestial.
But, Callie's mother didn't want that to happen.