I'm sure that everyone has at least once seen a story along the lines of "After Lisanna comes back, Lucy is ignored and leaves the guild to become stronger" or something like that. This is about the same thing, but instead of Lucy, it's Erza.
One day, before the S-class exam, Erza decides to leave on a 10-year quest. Everyone thinks that she can handle it, since she's an S-class mage, but what if she doesn't return? The guild members presume that their beloved Titania is dead, and mourn over her endlessly. The main members go missing during the S-class exam, and come back seven years later.
They hear of a mage guild called Sabertooth and learn that it is the strongest mage guild. When they participate in the Grand Magic Games, hoping to defeat Sabertooth and reclaim the title of the strongest guild, they have no clue that Sabertooth's strongest member, Red, has the same scarlet hair as their beloved Titania.
*This story is under major editing, and many events will be changed, for those who have already read this story. I will try my best to finish it as fast as possible.*
*MAJOR SPOILERS*
One year after Fairy Tail disbanded, and after the quest with the Dragon Cry, everything was going fine. The guild was back together. What could be better. But, the guild was morning for the loss of a fellow friend. One wizard was affected more than the others. No one was happy.
One month after the return of Fairy Tail, and the loss of a friend, five strangers enter the guild, and everything changed.
(I do not own Fairy Tail. Hiro Mashima does. I only one my OC's, and this story.)