Rebellion isn't something prepared overnight, but the eruption of long-accumulated contradictions.
The slavery system of the Southern Continent is like a powder keg filled to the brim with gunpowder, needing but a spark to unleash a massive destructive force.
It was only because the Ariel Empire had the Holy Church, a privileged institution above kingship, and the ruling class possessed unshakable authority and absolute military power, that they could forcibly suppress any rebellion.
However, that was in the past.
The Three Great Kingdoms and all the major independent lords were loyal to the Holy Church, loyal to Dragon God Airel, and the Dragon Clan was united as one.
But now, with the return of Dead Dragon Marlodis from the Underworld, the stability of the ruling class has been shattered.
And with the rise of 'Crimson Corruption Seyadis' and 'War Disaster Master Mondliod,' two Outer Gods, the Southern Continent has long fallen into a state of temporal chaos.