OK, wow. Apparently my misuse of the word plagiarism offended some people. My apologies about misusing the word.
I probably should have used story theft instead, even though that is still not the appropriate word.
But as I had clearly stated in my post, this is my feeling on the matter. Why do I feel this way? Again, it is explained in the post but here it is very quickly. Per the Author's Note that was left in the first chapter, they did not attempt to contact Unwelcome Storm on the matter. They just went ahead and wrote it. As I had mentioned, Unwelcome Storm has mentioned several times that this story is not dead and that she will be finishing it.
Instead of posting this in the Spacebattles or Sufficient Velocity (SV) threads, they created a new story on Fanfiction.net. Had this author just simply posted their work in the Constellations threads, then I wouldn't have such an issue (especially so they could be marked as an Omake). That is not what happened and again, this was also mentioned in my post.
It is all of these factors that makes me feel as if this is plagiarism/story theft. This author is attempting to steal/build off of the hard work of Unwelcome Storm. They are trying to boost themselves by using the reputation that Unwelcome Storm had built up.
A fanfiction writer does not have a legal team, marketing team, PR team, etc. They show their appreciation of the works of others by creating their fanfiction, fanart, etc. This also means that the only thing that these creators have, is the reputation that they build.
Unwelcome Storm has built up enough reputation and history that I know that I can read any of her stories and enjoy them. I've never been interested in the Persona games but I still read and enjoy her Worm/Persona story. I don't enjoy Taylor joining the Merchants stories but I still read hers.
This reputation is sometimes the only thing that they have. Unlike the large corporations (where a large group of people are involved in the creation of games or movies, or where the single creator is shielded by an army of lawyers and desk jockeys), fanfiction creators can be easily contacted. You can send them emails, make comments on their work on their various sites, etc.
Unwelcome Storm does pay attention to her threads, she does respond to them, plus you always have the option of sending her Private Messages in both Spacebattles and SV. But the fact that no attempt was made makes me believe that this is not a simple fanfiction of a fanfiction situation. This is an attempt to steal and use Unwelcome Storm's reputation to try and make their own story more popular. Or at least, that is what it appears to me.
I have read enough situations where somebody attempts to steal another persons works, where they try to claim that they are the original creator instead. Do I believe that this is going to happen? I don't think so, as they did mention the original story thread in SV. But I'm not going to encourage them.
Now, this post has gone on long enough. These are my opinions and I'm pretty sure that many people are going to have issues with them. I will not derail this thread any more by trying to argue my point against those that don't agree with it. But had there been an attempt at communication with Unwelcome Storm and that the story was posted within the Constellations threads as an omake, I would not have had an issue with the story. But since this did not happen, that is why I'm staying away from it.