Do we have Yukari's motivation for all of this, by the way? If it isn't conflicting with anything already, it would seem entirely reasonable that previously, people were questioning the necessity of the barrier for whatever reason, so Yukari decided to demonstrate why it was still a good idea by showing them a world without it. Of course, Yukari being Yukari, she didn't bother telling anyone that, deciding instead to just toss everyone into a big "game" (the revised "feudal system" rules), and letting people draw their own conclusions.
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Well, I'm feeling an outlining mood, so here's a general chain of events related to the human village that I'm throwing out there, if anyone happens to be interested in writing them; else, I'll probably get around to writing them myself in ~6 months to a year from now.
The window for the initial event firing should be between people adjusting to the new changes in the world, and everyone realizing that the outside world is just as suspicious of the humans as they are everyone else; this should probably translate to about 1086-1166, but I'd prefer more contextual triggers for that, if possible. The initial event should probably fire about one game in two, though it should be resolved before it has any significant effects most of the time.
The chain first starts as an event for Akyuu, where she hears rumors of people speaking of a vast land to the south filled with humans, with not a youkai in sight... People who, having won the fight against their own youkai, might be willing to help them with theirs. She can elect to dismiss the talk as harmless (the most likely choice), to try and quiet such talk, or to consider the option seriously. Silent events will begin to fire where such talk gains or loses support; the chain ends if support falls too low, or if the Human Village is at war with a kingdom on the continent.
If she elects to try and quiet the talk, she can elect to do so through more explanatory means or more forceful means; the first will be less effective, and risk backfiring if she is not persuasive, but if it succeeds, will end things there. The latter will suppress the movement and improve relations with all non-kind youkai-culture characters, but adds revolt risk to owned human-culture provinces, and ensures that further events that do happen, have less than pleasant effects. If she embraces the talk, it comes at a severe opinion penalty to all youkai-culture characters, and speeds the chain significantly. If she dismisses it, there's no immediate effects; it just sets the global flag to get things in motion.
After such talk is begun, an event fires for most of the other characters of Gensokyo ranked countess and above, bringing word that elements of the human village are considering bringing in outside parties to claim Gensokyo as their own; mtth varies depending on proximity to the village, traits, intrigue and rank, and this portion of the chain can be missed if it progresses to the next stage before the character can hear about it. Any non-human character hearing about it can elect to look into the matter, dismiss the talk as harmless, or threaten war should such talk not be dealt with; any human characters have the options of looking into the matter, dismissing the talk, or supporting such talk.
If characters decline to take the matter seriously, they won't hear anything more until the next "big" event, but if they look into things, they'll eventually learn over a couple of years (if Akyuu ignored the rumors) of a group of humans attempting to build support for sending an emisary to the mainland to secure their assistance in protecting the human village, and considering replacing Akyuu as a leader. If Akyuu supports the plan, they will learn (almost instantly) that the village is already preparing to send such an emissary, with her blessing; this will confer a significant opinion hit between them, and may lead to war. If Akyuu used force to suppress such wild talk, it will take nearly a decade for characters to find those responsible, but will learn that they are preparing to send an emissary in secret and to overthrow "That tyranical puppet of the Youkai" once they find an opportunity. In all cases, once the character has identified those responsible, they have the options of dealing with the matter on the spot, giving their information to Akyuu for her to deal with it (unless she's supporting it), leaving things there, or denouncing them to all of Gensokyo.
If they decide to deal with things then and there, they can attempt diplomacy or force; if Akyuu isn't involved, diplomacy is unlikely to be chosen or to work (though the odds of success increase with each character attempting it), but if it does, the matter is ended there, while force is also unlikely to work, risks hurting relations with Akyuu, and builds support for the movement if it fails. If it doesn't work (or they don't believe it will work), they can still inform the rest of Gensokyo of what they've learned. If Akyuu is involved, diplomacy almost certainly will not work, while force will almost certainly lead war. If Akyuu is exposed, it will trigger a crisis in Gensokyo, outlined later. If they tell Akyuu of what they've learned, she will be forced to either take a stance on the matter (she'll normally side with Gensokyo as peacefulyl as possible, if forced), or take a relations hit. If they ignore things, nothing further happens for the character until the next big event in the chain. If they reveal the plot, it speeds up everyone ele's investigation, gives Akyuu a chance to reconsider her stance (or improve her efforts to crack down on them, if that was what she had chosen to do), and has a chance of either building or removing support for the movement.
Though the odds of success are low, there's enough characters in Gensokyo that someone is likely to stop things this point unless they're all currently occupied with their own schemes; however, if things proceed past this point, things begin to get serious, and the tone shifts markedly depending on Akyuu's approach.
If Akyuu has declined to deal with the matter, and support for the movement has sufficiently grown, she is confronted by a large group of concerned villagers requesting that she step down from office, and new leadership be established. After a vote is held amongst a hastily called assembly of villagers, Akyuu is replaced by another young woman (most likely, it will need to be an OC) supportive of the movement's views; in deference to her respected position, no further action is taken against Akyuu, though she may still choose to relocate to another court should she take a sufficiently skeptical view of their plans. The news rapidly spreads throughout Gensokyo that new, hostile leadership rules in the human village, triggering a crisis; though the characters might buy themselves time by trying to interfere with their attempts to contact the mainland, the only way to resolve matters before they get worse is by conquering the human village.
If Akyuu has responded with a more repressive course of action, an angry mob storms her home, declaring a new era of leadership in Gensokyo. Akyuu is sentenced to death for her crimes, a new young lady is named as the village's duchess, and wars of conquest are declared against any adjacent counties. This news rapidly spreads throughout Gensokyo, triggering a crisis; the only way to resolve matters before they get worse is to conquer the human village very, very rapidly; the mission will reach the continent in a matter of months, and there's no way to stop it.
If Akyuu is responsible for this, she announces the readiness of the mission to great cheers from the crowd; she promises that with these actions, humans will no longer need to suffer the attacks of Youkai, and that they could finally live in peace. This news rapidly spreads throughout Gensokyo, triggering a crisis; though there is a chance to reason with Akyuu, if she listens at all, it will be a fragile agreement requiring great concessions, so it might be easier to just conquer the human village. There isn't much time, though; while their diplomatic mission can be interfered with, it's not easy.
Regardless of how it happened, though, Gensokyo will be in a state of crisis so long as the human village has chosen to align itself with outside powers; while this is ongoing, no unrelated major events will occur, there is a severe relations penalty between those aligned with the human village and all other rulers in Gensokyo, every ruler in Gensokyo has a modified conquest CB against the village, the village has a special CB against the rest of Gensokyo, independant rulers can plot to declare war on the village, and each ruler will be able to decide via decision to accept the new state of affairs. If the human village wins any of those special wars, an event triggers for other side wherein they are forced to accept the village's dealings with the continent. The crisis will end when the village is conquered, Akyuu agrees to end her dealings with the mainland, or 3/4s of Gensokyo agree to drop the matter.
Once the diplomatic mission reaches the continent, rulers in Europe will begin recieving events requesting aid for the village; those ruling coastal counties will recieve these earlier than others, as will those with higher ranked titles. European nations will have the option of demanding certain rights and concessions in return, of doing this in the name of God or not, and of whether they wish to offer significant aid, minor aid, or to join at a later date.
Once the negotiations are complete, nations offering significant aid will join all of the village's wars as an ally for the duration of the crisis, while nations offering minor support will see a penalty to their levy sizes in exchange for the village gaining raised levies via event. The human village will begin to see events regarding the terms negotiated on their behalf; most of them just translate to a loss of prestige or money, but more severe ones may require marriage, religious conversion, or becoming the vassal of an outside power. The human village isn't required to comply with the terms they negotiated, but there may be some stiff penalties for declining...
Similarly, while the crisis continues, there may be conflicts with the forces sent by the mainland, involving misunderstandings and cultural differences. At best, these might just involve some stiff opinion penalties for a short time, but at worst, those "allied" armies might decide that the village needs new Catholic leadership, and oust the leader in a coup. Needless to say, if that happens, it's also a significant event for the rest of Gensokyo; it quite thoroughly ends any attempts for the village to cooperate with the outside world against Gensokyo, and as such, Gensoykan powers can also attempt to restore the village as an independant duchy again. European powers, on the other hand, are no longer fighting for the right of the village to be wholly independant from Gensokyo, but rather for the subjugation of these unholy powers infesting the island.
Eventually the wars will end, however; if the human village loses, they are forced to accept the status quo, sever any ties with the mainland, and admit that the future of Gensokyo will be decided by the youkai. This may have implications for other event chains, but otherwise, doesn't mean much but a loss of prestige for Akyuu or the new leader. If the human village wins, on the other hand, the other counties and duchies of Gensoyko and their residents are forced to leave the human village alone, leading to many events regarding the enforcement of that agreement, and now presumably have powerful allies they can call upon if they wish to press their advantage to claim more of Gensokyo; if the village replaced Akyuu as leader by event, they have a shiny new CB to do just that. Those allies don't come cheaply, however; while there wasn't much time to bicker and renegotiate during the war, the village has few excuses for failing to comply with their agreements now, so breaking those terms now come at a much higher price... And refusing to convert or become a vassal, if they had agreed to it before, now comes at a strong risk of war.
There's... Probably more, but I think I'm done outlining for the day. Hopefully this will be of interest to somebody!
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