This plot is part of the Weakening of the Veil plot arc.
After a thousand years of peace, the magical barriers which have separated the world of humans (Elder Soteria) and the world of the fae are breaking down. The fae are eager to return to their lands. Since the barriers are still somewhat up, the elves and dwarves cannot return all at once, but rather the most persistent and potentially most upset of each are the first to return.
The dwarves and elves were not meant to be banished, they helped put up the walls which banished them unknowingly. They are angry at humans and feel betrayed. They would like their ancestral lands back.
A few Fae have been seen, though far no one returning from the Dark Aether it is only a matter of time. This initial act is very simple, a few of the mistakenly banished light Fae from the Dark Aether return to Elder Soteria and meet some of the locals.
In this act the returning Light Fae must be either convinced to make peace with the humans left behind after the Backlash or go to war in retribution.
This will require players to either make fae or humans native to Elder Soteria.