Deep within the Aphotic Sea, there lay an island named Aistra, perpetually shrouded by fog.
The skies above were forever enveloped in pitch-black clouds, accompanied by deafening thunder, when a group of Winged Folk with feathered war armor descended from the sky.
They hailed from a distant Sky City, having plundered through the Nine Seas due to resource depletion; Aistra, rich in abundant and undeveloped extraordinary materials, had long been their target.
Decades ago, the great overlord who ruled Aistra had temporarily submitted to the Winged Folk, but their leader had recently died violently at the hands of the King of Glacier People, prompting him to seize the moment to rebel.
However, before officially plotting the "rebellion," it was necessary to gather an overwhelming force. Thus, the great overlord sought help from the "Mo'er Security Company" under the Fischer family, the hegemon of the White Sea.