Hello, I remember a conversation about this on the Chrono Cross GameFAQs message board a while back. I was the one that submitted the Universal Porre Uprising theory. It kind of used every theory and combined it into one. I'll re-post it here, I remember there were a few changes that needed to be made to it, but I can't really remember which ones.
Universal Porre Uprising Theory
*Disclaimer* - I do not claim to know everything, I’ve probably made quite a few mistakes, but, that’s what this theory is for. Coming up with some sort of idea why Porre, a peaceful town in the Zenan continent, slaughters the Guardian people and take over their land. I saw the many theories on Porre’s uprising at Chrono Compendium and decided to see if I could combine most of them. I used creativity and the void of explanation to create what seems to me like a good theory as to what happened. Once again some of my theories and their links to one another are built on what I thought I remembered (which means I’m not sure on parts). If there is anything wrong with what is based on storyline please let me know.
Here we go!
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After the events of Chrono Trigger, Porre is changed by what Chrono & Co. did on their adventures.
Fiona’s Forrest creates a barrier between Porre and the rest of the Zenan continent. The people become more independent and start using the forest for resources.
They become more militaristic and more materialistic, having an underlying jealousy of Guardia and the power that the kingdom holds over them, with the bragging rights of having the Masamune, the Rainbow shell and of course an all powerful hero couple/King and Queen. Porre and it’s people obviously were longing for power of their own.
Porre is first to send explorers out beyond the Zenan continent in the hopes of finding some land to expand upon, and gain more power and resources.
Porrian explorers stumble upon El Nido and try to take a claim at the land but are promptly defeated by the resident Dragonians and their powerful Elements.
The explorers return to the mainland and productivity of weapons is accelerated. Porre creating “guns” and variations of guns based off the weapon created by Lucca.
Porre mounts a sizable force and invades El Nido. The tactically advanced Porrians win the land but do not obtain control of the powerful elements used by the enemy.
Several years later plans for Chronopolis are initiated by Guardia, Porre willingly helps Guardia by hosting the facility on “new found” land (El Nido).
The Porrians lead the Guardians through El Nido’s only entrance making sure to stay away from all the other islands and end up at the Sea of Eden, a secluded place within a secluded archipelago, an easy place to get cut off from the Zenan continent.
Guardia not knowing Porre has any ill-intent thinks nothing of the act and continue on with the building of Chronopolis without even thinking of what was outside of the Sea of Eden.
All the while Porre’s development is continuing in the rest of El Nido, now stumbling upon new technology left behind from the Dragonians. But the Porrians run into trouble, The Dragon God. Not all too happy about the extinction of all it’s subjects it wreaks havoc on the Porrians greatly hindering their work. That’s when FATE becomes a thought.
The Dragon God is also creating disturbances at Chronopolis so FATE becomes more than just an idea with the intention of doing something about the Dragon God.
The Guardians and the Porrians work together with the help of the Motherbrain computer chip (apparently either had records of it made by Lucca or actually brought from the future by Lucca) and the Dragonian technology discovered by the Porrians (passed off as “Porrian” technology”) to create the first working model of FATE.
FATE was able to trick the Dragon God into splitting itself up and that’s when it sealed their powers, making them lose control of the elements and contribute to Porre’s power. The Guardians only see it as a defeat of the Dragon God and not a victory for Porre.
Chronopolis is completed and research is started on time travel (Initially what Chronopolis was created for among other research).
The Time Crash occurs years later and Chronopolis is sent back in time.
The Porrians seize the opportunity and kill off the Guardians. They modify FATE, then bid their time advancing even further beyond the the flesh transferring their form onto the ghostly beings found inside Chronopolis.
When the supposed starting chain of events begins, immediately after Chrono Trigger ends, the Porrian remnants from Chronopolis (Easier referred to as Chronopolians now) visit the Zenan continent and make appeals to their freshly power hungry, past, selves.
The Chronopolians supply their advanced weapons and the Elements to the people of 1005 A.D. Porre.
Porre throws together a large force and marches into Guardia.
The Guardians are slaughtered, the Masamune is stolen, the Porre enslave the Demi-Humans of Medina, they are told of El Nido by the Chronopolians, invade, slaughter the Dragonians (with the Dragonian races’ own device, Elements), Chronopolis is already there because of the Time Crash, so FATE already exists, the Masamune ends up discarded and tainted on the Isle of the Damned, the Porrians and the Chronopolians pervert FATE’s programing to control people through the Records of FATE, once again the Dragon God is suppressed, and the Porrians now have control over both the Zenan continent and the El Nido Archipelago.
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If there is any flaw in my reasoning, if I said anything that is wrong storyline wise (not theory based) then please correct me (I’m not too sure about the Dragon God being “tricked”, I forgot how things happened).
But this basically combines several theories and use a lot of creativity on my part. Hope it enlightened, confused or even disgusted you.
Thanks
~AX~