Cynlluniau Sidhe translates as "great plan of the Elves". It is the most significant alternative to the gheallie Sidhe. Like its rival, it is concerned with restoring Sidhe dominance in the forests and extending those forests, thus restoring the golden age of elves in Cerilia. The cynlluniau Sidhe aims to achieve this end not through direct violence but through subversion.

When the humans first came to Cerilia, the elves tried to teach them to live as they did, in harmony with nature such that they would not disturb the Mebhaighl that flows and pools in the land. The elves were able to induce a few humans to accept this transformation, and taught them the secrets of arcane magic. However, nearly all the humans arriving in Cerilia had no desire for such a transformation and went about making the land suit their natures, destroying the land for the elves.
A great divide separated the elves. Some, like Rhuobhe Manslayer believed that the war against the humans should continue, while another faction, under Tuar, Queen of the Elves, believed the elves should organize the program of transforming humans into half-elves, the Hanner Sidhe. Not with an eye to to slowly turning the humans one by one into half-elves, but to transform key humans and send them back to be leaders of human domains, subverting those domains and leading them to a proper relationship with nature as the elves required. Azrai's influence swung many elves to Rhuobhe's demands for blood, and the Queen acquiesced.
War followed, culminating in the battle at Deismaar. There, Tuar persuaded most of her fellow elves to abandon Azrai before he could double-cross them. Elven forces helped the humans destroy his forces, and some elves even claim it was Rhuobhe who made it possible to "kill" Azrai. But Rhuobhe did not switch sides, determined to slay all that were not elves. Tuar and most of the elves withdrew after the gods were destroyed. Tuar did not escape the battlefield, and her fate remains unknown.
Without Tuar, division again paralyzed the elves after Deismaar. New elven realms formed in the other forests, isolated from each other by human or awnshegh realms, and these took up a variety of positions. Some advocated the gheallie Sidhe, others proposed simply temporizing, and many did not believe Deismaar turned out well for the elves and hoped to avoid conflict. Indeed, the majority of elves pursued no clear policy. Rhuobhe Manslayer seized a place in the south-western Aelvinnwode where he hoped to bring the gheallie Sidhe near the heart of the newly-forming Anuirean Empire. Without the cooperation of the general elven population, all he could do was raid that strongest human realm.
It was not until Fhilerwyn Llyrandor came to the throne of Tuarhievel that the program of of cynlluniau Sidhe again had a champion able to put the great plan into practice. While a few humans had been transformed during the interregnum, Fhilerwyn focused on discreetly selecting and grooming a future group of leaders. Today these are the most powerful, well established Hanner Sidhe. Laela Flaertes, Duchess of Tuornen, and the High Mage Aelies are but two of Fhilerwyn's protégés. Fhilerwyn's unified Tuarhievel drew the attention of the Gorgon. He who had been Raesene Andu had brought neighboring goblin and dwarf realms under his rule, and turned on his elf neighbors. Fhilerwyn was slain in the war with the Gorgon, but his wife, Ibelcoris Llyrandor took the throne and assumed guidance of the cynlluniau Sidhe.

Ibelcoris recruited many remarkable people to become Hanner Sidhe over the past two and a half centuries. Some, such as Torele Anviras and Fhiele Dhoesone have begun their leadership roles in human lands near to Tuarhievel. The current Prince, Fhileraene has selected more Hanner Sidhe, including most notably, Savane Mhoried. Eriene Mierelen and Kalien's widespread guilds may also serve to keep the Prince informed of events within the ruined Empire.

Using the cynlluniau Sidhe can be a rich source of intrigue in a campaign. Humans are unaware of the great plan or its ultimate purpose. Many do not even understand what a half-elf is. Half-elves themselves may encourage the error that they are the offspring of human and an elf, since that is less disturbing to most than the truth. Half-elves are quietly introduced in small numbers into human society so that each generation of humans accepts the long-lived friend of the elves more easily than the last.

Elven realms are still divided in their approach to humans. In Tuarhievel, the two factions are sometimes called traditional, those that support the policy of gheallie Sidhe, and progressive, those that support cynlluniau Sidhe. Other sidhe realms' policies include total isolation, such as Tuar Annwn, or attempts to mix the populations, such as Innishiere. Coullabhie and others have tried to form alliances with human realms, with mixed success. Lluabright prefers the path of the gheallie Sidhe. So far, only Tuarhievel has developed Hanner Sidhe as a coherent part of the cynlluniau Sidhe.

This unfolding of the plan is an example of how the later stages of the cynlluniau Sidhe might unfold. Such things are entirely dependent on how the Dungeon Master has begun to unfold his campaign, so are in need of adaptation to make the most sense.

• The King of Tuar Annwn lifts the veil that wards his realm and convinces Llaeddra of Lluabraight that the time has come, their gheallie Sidhe begins it work and both realms begin slow expansion -- starting with nearby awnsheghlien, goblins, orogs and gnolls, so as to impress but not too soon frighten the humans, putting the cynlluniau Sidhe on notice. They have a little more time to work but also a hint of threat to perhaps speed it up.
  
• Once these outlying Sidhe realms are joined by Isaelie Galanohel of the Sielwode and Rhuobhe Manslayer more dangerous abominations will be confronted.
  
• When Fhileraene Llyrandor receives word that the great plan is being put into effect, he puts his assets of the cynlluniau Sidhe to work.
  
• Conflict is fomented between Ghuralli and the Rjurik in the Giantdowns, the elves maintain the balance and keep the conflict at a boil so that both sides kill each other off. Hanner Sidhe "druids" who have been placed in those communities will convince the Rjurik to ask the elves for help and the Giantdowns will suddenly be a protectorate of Tuarhievel. The Rjurik will nominally be happy citizens, but in fact they are servants no less than the goblins were eons ago.
  
• The arrangement between Dhoesone and the goblins of Thurazor is a Sidhe plot to being about the destruction of both the guilds and Thurazor. When the time is right, conflict is sown between them and the guild war, kept active by the Sidhe, and spreads to Thurazor, in phase II of this operation, Dhoesone and Talinie invade Thurazor and the goblins are destroyed with human cost.
  
• Savane Mhoried in Mhoried prepares the realm to deal with the most outrageous guilder in northern Anuire, Mheallie Bireon. But while she makes these preparations, she waits for Talinie and Dhoesone to be ready to cooperate to completely destroy the first human realm to fall to Sidhe plans. Note, all the while no elf dies, always humans fight these battles and elves move in from behind to take control and settle the problems as saviors and protectors.
  
• In Tuornen, a serious battle between the Manslayer and the humans ends with the destruction of a human army. Braedonnal Tuare is in the north watching affairs in Thurazor and the Five Peaks as Dhoesone and Talinie move against them. Braedonnal moves south and the Manslayer withdraws. Tuornen supports Talinie and Dhoesone in goblin affairs and cooperates with Mhoried regarding Cariele. Alamie is scouted in preperations for phase IV.
  
• Agents from the High Mage Aelies, Mhoried, and Hanner Sidhe] agents in the Sielwode prepare the Eastern Marches for war, fomenting war between Osoerde and Ghoere, which will ultimately become a general war as Coeranys and Elinie are dragged in on opposite sides. Once Cariele is crushed, Mhoried and Aerenwe intervene in the war, on whatever sides make the most sense, ?sides? are immaterial. Key forested places will be seized and elves brought into tend and protect them, while the humans spend themselves in war against one another. Alamie will be brought into the war by subversion, charms, espionage, or gentle prodding. Then Tuornen and Mhoried will crush that realm with harsh abuse. Refuges pour south and it goes mostly unnoticed that Cariele is now devoid of humans, having fled or been slaughtered.
  
• By now it may be possible that wise counsel in Anuire or elsewhere might be alert to a Sidhe master hand behind everything. These figures are long known to the elves, who 1) either employ them to misdirect ?Manslayer is behind a plot to seize the Iron Throne!? 2) or they are discredited in advance, or 3) they are simply killed.
  
• If by now the other faction of elves, the non-accomodationists of the gheallie Sidhe don?t recognize that the humans have both advanced Sidhe purposes and destroyed themselves, they have missed a great opportunity to gain control of half of Anuire and use it to destroy the other half, and then turn elsewhere. Ideally all this has been going on while the elves move on abominations and humanoids directly.
  
• In the north, once Cariele is vacant, Talinie is prepared for a war in Boeruine with Tuornen under the command of Braedonnal Tuare, Torele Anviras, and other sidhe agents. If Braedonnal?s work with Manslayer has been effective, by now he sees the virtue of Fhileraene?s plan and initiates his own invasion of Boeruine. Talinie and Tuornen engage in talk that sounds like moving to aid Boeruine, but they invade as well. Once Boeruine is taken, humans are driven from the forest and the southwestern Aelvinnwode prepared for re-sidhification.
  
• Humans in Dhoesone and Talinie are taught, coerced, or forced to adopt Sidhe care of the forests or move to the plains. Humans are gradually made into servants of the elves. Quietly without them even knowing, on the basis of war-time necessity or whatever argument makes sense on a local basis (building on work done by the Hanner Sidhe already).
  
• Forces from Dhoesone are used in Boeruine or against the abominations as the elves see fit. Elves now defend Dhoesone from the Rjurik.
  
• Treaties are made with the Rjurik guaranteeing their realms and borders, and the lands of west of Stjordvik and Hogunmark are saved for later.
  
• By now it is expected that all human realms remaining in Anuire are fighting against the Tuarhievel coalition.
  
• The elves will govern like the Romans, insurrection will be crushed by genocide.
  

Humans will generally fall into three categories, 1) those who must be killed, 2) those who may serve, and 3) those who are taken back to the Sidhe homelands to be trained as Hanner Sidhe and to eventually rule as intermediaries between the humans and the elf lords.
Perhaps the most anti-human will be happy to see 60% of men killed, 30% serve, and 10% lead, while the less anti-human might be happy to see 30% die and 60% serve, and 10% rule. The humans will now either learn to live in harmony withe the land as the elves originally intended when humans first arrive in Cerilia, or they will die as occasion presents itself. Either way, the elves rule.