I think the early communists had some really good ideas and I always like the idealist good communist that sometimes showed up in cold war movies. I wanted to incorporate something like that into the setting, but didn't have any good idea how to do that in a pre-urban society. Now I played Dragon Age 2, and the Qunari gave me a lot of nice ideas that might work out well.

Unity is a philosophy as much as it is an organization, and the two aspects are tightly connected with each other. It is also a religion in many respects, but it does not worship any gods or spirits.
The core believe of Unitiy is that single thing is part of a larger collective. A tree is not just a single tree, but a part of a forest, a bird is part of a flock, and a mountain is a part of an island. Nothing exists just by itself, but it is the relation to other things and the role it plays in the larger collective, that defines everything that exist. A fish is nothing without the ocean. The plants that feed it and the larger animals that eat it all define what a fish is. And most imporantly, a man, even with his house, and his fields, is nothing without the other people of the village. Only by having people who work on his fields, and people who buy his crops and sell him leather, furs, and tools, can he be the person he is.

Few people dispute the logic of this, but the core principle of Unity is, that this dependency persists through all thinkable level. The forest, mountains, and rivers form continents, and the continents and oceans form a planet. Eventually, everything depends on everything else. If just one tiny thing would cease to exist, everything else would be different. The unity of everything that exists is called the Monad, which is the only thing that Unity has similar to a god. Because everything is an equal part of the Monad, everything is equally important, and everything has the same value, which includes people, spirits, and gods. All people have to be treated according to their capabilities, which means that it makes no difference what age or gender a people have, to what race or clan they belong, and if they are nobles or slaves.

This puts Unity in strong contrast to the values and customs of many of the people of the Barbarian Lands. While age, gender, and social status have different meanings in different tribes, a persons clan is of very high importance. The needs of the clan stand above the needs of anyone else and while other people may be a guests or an allies, they don't have any of the rights and previleges that members of the clan have. It is a duty to help and protect others of the clan, even if one does not like them, and that is more so true for everyone who has been granted hospitality. But there is no ethical prerogative to extend any such help to strangers and outsiders. They are not your business and don't concern you. Offering help to strangers is both admirable, and regarded as a sign of weakness. The duties to the clan include not risking your life or wasting resources of the clan.

In the teachings of Unity, these separations do not exist. Every person is a member of the world, and has the potential to contribute equally, regardless of ones birth. So the second principle of Unity is, that everyone is a brother or a sister. No one is closer or more distantly related to everyone else, everyone shares the same social status, and there is no seniority between people. If one person deserves to be treated in a way, then every other person in the same situation deserves to be treated in the same way. However, the followers of Unity have many enemies, so these benefits can only be extended to those who are willing to accept being part of the Monad. Those who refuse this universal truth and try to resist it are a burden to Unity and can not be granted the benefits they have a right to, as they would only waste them. However, followers of Unity are still a lot more likely to offer help to strangers, in the hope that they can be helped along the path to realizing the truth of the Monad. But when followers have to chose between other followers and outsiders, followers always get preferential treatment. However, Unity teaches that there must be made no difference between a highly respected elder of Unitiy, and a follower who has just converted. Still, people rarely dare to join Unity out of a whim or to get out of a tight spot, as they treat apostates as traitors who abused their hospitality and protection and stole resources that belong to other followers. Also, everyone who wants to become a follower has to renounce any former rank, status, or clan, and few clans would be willing to take such a person back, leaving them outcasts with nowhere to go to.
It is very uncommon for followers of Unity to be found in the communities of other groups. People who forsake their clans and join Unity usually move to other Unity villages or join Unity enclaves in larger towns. Followers of Unity are encouraged to answer any questions about their believes and customs that other people have, but usually are not actively trying to win new members to their cause, so to not overly antagonize their neighbors. However, in regions of very strong Unity presence, it is commonly attempted to get any pockets of remaining outsider to join, even if it takes very strong coercion.

While everyone in Unity is of the same status, not everyone is of the same skill, and duties and authority are given to people who are best suited to perform them. Unity does not have any specific ranks for its members, but rather asignments. It is the office or position that gives a person authority and command over other, and they are all lost when another person is asigned to it. Stability and continuity is recognized as important for everyone to understand ones own role in the Monad, so posts are usually only reasigned when the current holder becomes unable to perform his duties optimally, and not every time another person shows superior capabilities. Only when people truly understand their position in the community and their relationship to the other people can they perform their duties at their best, and according to Unity, even a change to a small part changes all the other parts as well.

While Unity allows for personal possessions, everything of value to the community is shared possession by all followers of Unity. Personal possessions include clothes, simple tools, toys, and simple jewely, as long as it is made of nothing more valuable than bronze or iron. Armor and weapons belong to the community and are distributed by the administrators of the guard, but usually every soldier is given a set of equipment that is assigned specifically to him and he alone is responsible for it. However, any equipment taken from fallen enemies has to be brought to the guard administrator on return to the village to be given to the person who could make the most use out of it. Usually preferential treatment is given to the person who brought the item in, to encourage people to not trying to hide any valuable finds. Items of purely luxury use are collected and sold.

The religious practices of Unity focus primarily on helping all people understand their capabilities and their relation to the world around them, which both define their identity in the Monad. By understand ones own position and identity, one can also gain understanding of the other things and people that depend on oneself, which further increases the efficiency of the Monad. It is said when a person attains full understanding of his own nature and identity, he will also gain complete insight into the Monad as a whole, effectivly ceasing to be an individual. A person who has reached full Unity no longer fears death, because the Monad is eternal, and even through body and spirit die, it is only the natural change of the constantly shifting Monad, with nothing having been truly lost.
The priests of Unity are known as the Mystics, who can be both divine and arcane spellcasters, but only divine spellcastes are trained. All arcane mystics are converts who were mages before they joined Unity. Magic is a part of the Monad that lies beyond the world of physical experiences and is therefore regarded as a fundamental part for deeper understanding of the Monad. While most followers of Unity gain understanding of the Monad through meditation and contemplating, those who show the spirit of the true seeker are initiated to the path of the mystic. The mystics are not only the teachers of the followers, but also highly respected for the magical powers they gain from their study of magic. To cast spells is to perform close to the full potential of the Monad and regarded by followers as a display of the divine. However, at the same time, followers are considerably less weary of magic than other people. While they recognize the danger of magic in the hands of an enemy, they also understand that it is the work of a mortal and that every person could potentially master such a skill. There is however some resentment for spellcasters who do not follow Unity, that goes beyond the usual weariness of outsiders. Magic is a manifestation of the Monad and using it to harm Unity has an air of heresy to it.

Since stability and certainty are of high importance in Unity, followers have relatively strict customs when it comes to personal freedom. While all people are expected to find the place in life that is right for them, one can not simply be constantly changing ones mind on a whim. If something is started, it has to be done with the conviction of seeing it through to the end and not merely attempted half-heartedly. If one is unhappy with ones assignment, it is expected that one can explain the reasons for it and also being able to say what kind of asignment would work. If someone is repeatedly causing dissent, he is asigned to low-competence duties of no vital importance until a better solution can be proposed to the administrators.
While Unity does not have marriages, it is required that all romantic relationships are commited and have to be declared before the community. Casual sexual relationships are forbidden, which includes any relationships with outsiders. Not only do they often cause disruptions of communal life, followes of Unity are also expected to clearly make up their mind before doing anything and personal relationships require the greatest degree of certainty. Unplanned pregnancies only cause disruptions of daily routines, not only for the parents but also for the people depending on their work, and couples are strongly requested to make sure it doesn't happen when inconvenient. Pregnancies do not have to be permited, by expecting parents are required to inform their superiors as soon as they know, so they have time to plan ahead.
While children live with their parents, all Unity communities have some members asigned to caring for the children while their parents are working. When they are old enough, they start to be trained in some basic and minor asignments that are common in the community, like sweeping floors or feeding chickens. As they become older they are asigned more complex tasks that help them learn about all the duties that are performed in the community. Eventually, they are asked to name preferences for available assignments and will serve for a trial period until they find a duty that both fits them and for which are deemed suitable by the older workers. As not all people are equally suited for every assignment, it is regarded as very important to find one in which the child will be able to perform to its full potential, which should not be wasted in an assignment that only makes the child discontent.

While not as large a power as some other kingdoms and alliances, Unity is massive in size when compared to other clans. In the northern Barbarian Lands, about 1 in 12 people are followers of Unity, with considerably higher numbers in the lands of the Kaas, where it is one of the major powers. Unity has the greatest support among the Kaas, who dominate the highest levels of assignments. But the farther south one travels, the more the numbers of kaas are replaced by elves and humans. But since Unity usually maintains one a small number of strongholds in a large region, most villages have a highly mixed population. While the distances involved require a great amount of authonomy from remote communities, Unity takes great care to maintain constant contact between groups and villages and enclaves can count on assistance from several neighboring settlements.

I think this looks already quite solid, but if you have any idea about what to add or change... well, you know the drill.