A fandom is never that unique. It differs in what the fandom revolves around, but the way a fandom evolves and splinters is always the same; only characters and locations change.
In the beginning, a fandom consists of just its creator and those involved in the production of the fandom. Then, word spreads. People mention the fandom to others. They mention it in their Facebook status, write about it on their blog and demand official merchandise. Despite these demands, they make their own with what talents they possess. They write stories with the new characters, draw pictures, edit any photos released of the new fandom, make cloth toys and various other fandom-related acts of creativity.
The fandom grows. It gets exposure in media and spreads to other countries. People all over the world are starting to learn of it. It's not enough to simply use their creative outlets to participate in a fandom for their own pleasure anymore. The fans now feel like they must be connected with other fans so they can compare their thoughts and feelings. They need to feel vindication that they are not crazy in their fandom and that others have like-minded ideas. In this intermediate stage, all theories are appreciated no matter how crazy they seem.
People soak up everything like a sponge. This leads to the creation of special boards and communities for the purpose of this fandom alone.
By this point, the fandom is incredibly lucrative. In fact, those who create the fandom have started capitalizing on it with ever more official merchandise and appearances at conventions. In fact, they may even have conventions that are just about the fandom in particular. Fandom is pairing off in support of particular players within the fandom. They may have their own Facebook, communities or boards just for that person. These are the glory days of the fandom or the honeymoon stage to put it a different way. Those involved with the fandom in both the creation and the participation of the fandom can see no wrong in what they do. Everything that is official canon with the fandom is wonderful and they can't imagine a time when it couldn't be that way. This time will be coming soon. Already, there are fans who argue about the interpretation of certain things within the fandom. Others may start believing that they know the source material as well as the people creating it. If something happens to go against their idea, they may become confrontational or simply refuse to accept certain things as canon despite all the evidence.
Once cracks begin in a fandom, a schism is unavoidable. Something will happen. Something will occur to make these cracks splinter through fandom. When a fandom breaks, there are two usual causes: a change in relationship between two characters and/or the death of a character. At first, the event is shrouded in secrecy and rumors. Those in the fandom with connections to the creators claim that this will happen. The reactions to these rumors will mimic what's to come. Some will agree it will happen because it's the worst thing to happen and they feel that the worst thing to happen always does in a fandom. They may also blame themselves for jinxing it or causing it to happen. Others will disagree that it will take place because it's too horrible an idea. These two will later form the basis for Group A. At the same time, there will be those fans that are overjoyed at the thought or feel that the creators can do no wrong so it must work out for the best somehow. These two will form the basis for Group B. A fifth set of people will claim that none of it matters because they care only about the story and don't form a personal attachment with the characters themselves. The sixth and last set of people will not believe rumors on the principle of being a rumor. Even if something reaches the status of being a spoiler, they will not believe until the act finally occurs and becomes canon. These two will not be a clean merger with either Group A or B. They will separate one by one into either.
The day it happens, the fandom is already irretrievably broken. It just doesn't know this yet. First-hand experiences and feelings spread like wildfire through all personal communications: Twitter, blogs, Facebook, email, phones, etc. In discussing what has happened, they start to form or strengthen alliances. Group A hates whatever happened. They feel it's the worst possible thing that could happen to their fandom and the creators must have had delusions of grandeur if they thought fandom would accept this. Group B believes that if it is canon, they must accept what happened and that it must have been the best possible outcome because the creators know everything. Both groups feel that the other is crazy and will come to their senses at some point and realize the other one was right all along.
The communities and boards will have posts and threads about what has happened. The people who will come to represent both groups will begin attacking each other on these immediate posts and threads. Group B believes in canon and this can lead to a degree of haughtiness in their posts. Group A knows this is true; that canon is what they've always believed in before but accepting this new development as truth is incompatible with what made the fandom special for them. However, they start feeling insecure. They begin to wonder whether Group B is correct and they need to mourn the end of what they held dear in that fandom and move on. They create more posts and threads to see if their point of view will be vindicated by others. They align themselves with those who agree and argue with those who disagree. Group B starts becoming tired of Group A. They ask that Group A stop posting their opinions and accept what happened. Group A now equates Group B with the fandom creators which would mean that some are viewing them as the enemy.
Group A will be made up of people who mean well, but a few will make it seem as though it's bent on violence and discord. These few will threaten violence on the creators of the fandom whether they live in Los Angeles, Cardiff or Edinburgh. Most within Group A will be embarrassed by these actions. They will come up with a more peaceful approach of petitions and letter writing. However, Group B is becoming increasingly unpleasant towards Group A especially with the threats of violence it assumes represents the group as a whole. Group A needs a refuge so it creates its own communities or boards for their use only. In these places, they are free to discuss their feelings and have them confirmed by others feeling the same way.
Within both Group A and Group B will be the gophers. Gophers are go-betweens. Just as they work between stage and crew on a play, gophers try to main friendships between Groups A and B. They are usually more sensitive than most and take the schism as badly as a child of divorce. They want nothing more than for everything to as it was...they will come to realize that it can never be that way again. Gophers often suffer for their part. They understand how both sides feel but are powerless to make them understand each other. Gophers may also be caught between feuds involving former friends and they may be attacked themselves for still maintaining friendships in both groups.
There will be those in Group A who say they are done with the fandom. They will pledge to burn the dvds, cds, books and merchandise as well as not paying any more attention to it online. Some will do so, but most will not. Most will continue with the fandom in the hope of having the previous event rectified. If it is undone, some members of the groups will be reunited, but most will maintain their new relationships. A small number of those who didn't give up the fandom enjoy the attention they receive when claiming that they'll do it. They like when people beg them not to and this makes the experience worthwhile. Months or years later, they may still be found in the fandom.
Like what happened when a fandom is new, both groups express their feelings over the event with creativity. They make music videos, wallpapers and other things, but the most important thing they do is fanfiction. Group B works out their feelings by writing new adventures with the new information. Group A pretends as though it never happened or creates a way in which the previous canon can be restored: a fix-it story.
As time passes, members may grow dissatisfied with the fandom from the infighting, additional fandom decisions made by the creators or finding something they like better. They will move onto new fandoms. The process will begin anew. However, those from Group A in one fandom are more likely to become Group A in their new fandom. If they have been "mistreated" by creators in one fandom, they won't hesitate to feel it could happen again. They may be jaded and quick to believe the worst in rumors as spoilers.