I meant to say "Ruler" where it said "Overlord" I fixed that. King Ramner is definately a royal.
You are very much correct that this is all Royalism propaganda. While popped units come with an innate understanding of the rules of their world, they don't know anything about the history. You definately have to take anything said by anyone in this story with a grain of salt. Especially a priest of Royalism. The things that are obviously false about the story are:
1) The Three Tools did not work together to summon Parson.
2) Parson came to Erf before Wanda attuned.
3) None of the Arkentools were involved in summoning him.
But this version of events fits in the dogma of Royalism better. It forms a morality tale of how defying your natural place in society and your Royal Ruler leads directly monsterous ends.
One of the things I love about Erfworld is how very many concepts it is touching on. One that really catches my attention is the religion concept.
Royalism is obviously the orginial religion. It is hard to know where the propaganda ends and sincere belief begins. But in the end it serves to keep the units in line and motivated. For untold turns the combination of this religion and the natural loyality of units for their popped side, have kept sides stable.
Toolism is its first major opposition. The wielders of the arkentools are much more visible signs of the Titan's mandate. My expectation is that the knowledge that the wielders exist and they are superior to royals will fundamentally weaken every royal side. After all, before the typical unit knew there was an alternative, he was more likely to put up with abuse. Afterword his loyalty would probably be more prone to falling.
Liberty is a religion that is still in its embrodic stage. As Parson moves through the world, the units that he treats humanely like him more and more. They also start looking a their world in ways they never contempated before. If that is not the start of a movement I don't know what is.
One important thing to point out is my personal hypothesis is that it is actually not that hard to desert or turn on your own side in Erfworld. We already know from the summer updates that Princes will often turn their own Ruler's in power bids. If it was impossible to leave your own side, then any Ruler would just disband the rebel and that would be the end of it. We have also seen non-Royal units twist Duty and Loyality in ways that are actually determinatial to their side. Also what is the point of a Loyality score if no one can rebel? My hypothesis is that the reason that units so rarely rebel is combination of naturally high loyality to their popped side, fear of reprisials by their old side, fear of being alone (these people are popped into a world that had rigid social structure that heavily promotes unity), fear of disbanding by starvation, and religion.
The story I am writing is long after Toolism and Liberty have both left their infancy. Royalism had to evolve to keep up. It became more zealous. Like the the King of Transvilito's belief system it has firmly couched itself in the idea that Royalism is the natural state of the world. To deny it is affront to all that is sensible. While being descendant form the first Titan mandated rulers is still important to the message, the emphasize has moved to playing on the fears and hopes the individual unit.