@Lenko ?? They are pretty there to make the story not only about the same people all the time, they will probably be used to develop the main cast, this is how to write a story 101, dude.
This manga is actually focusing a lot more on romance, which is a part that Fairy Tail really needed more IMO, I think this is actually better than what the main-series was.
Such a good ending, funnily enough I had read the first chapter of this one when it was released and then couldn't find it, now that I found it, it was already complete, such a good feeling!