(this one will be quite short this is my first attempt at an angst type of one shot so if you don't like angst then you don't have to read it, just move on :D )
The guild was in a massive fight you and everyone else had just gotten back from Tenrou island which apparently you were trapped on that island under a Fairy Sphere for seven years. But now we had to stop this clock which was taken over by the new Oracion Seis, Erza your girlfriend was fighting Cobra and you knew that she could handle him. You, Natsu, and romeo were fighting " Michelle " and midnight and she was being an obsessed-over-protective-sister. Natsu was fighting michelle while you were fighting midnight.
He was tough to beat, you thought he was stronger than you he used one of his strongest spells on you. Natsu tried to take the hit cause he's dealt with that same spell before. Your also a dragon slayer, You're the gold dragon slayer, Your dragons name was treasure She taught you all of her dragon slayer secret arts. One of them would defeat michelle and Midnight but it would cost something very dear to you and everyone..
which is...
your life... the only people who know about this is the whole guild. it's called golden rush. It costs you your life but you not completely gone your turned into a little diamond and gold necklace. you thought about using this spell... of course it would hurt but your spirit and soul will always forever stay in Fairy Tail and maybe one day Porlyusica can reverse the spell or whatever.
who knows but you had to do this.. For the Guild " GOLD DRAGON SLAYER SECRET ART- GOLDEN RUSH " It blew everyone back but defeated Midnight and Michelle who turned out to be a doll, But before you were full gone Natsu yelled " NO (Y/N)! " the last words you said were " tell Erza i love and cherish her, and i will for all the time my soul rests, and for you and everyone in the guild i want you to know i did this For The Guild "
Natsu was already crying so much Erza was too she knew you had cast that spell and now you were probably gone forever. When Erza saw the necklace that you had turned into she read the engraving on the back which said the exact last words you spoke.
Erza was so broken... knowing that the person she loved and cherished most gave up their own life for this guild.. and for her. Erza hope that maybe Porlyusica can reverse this but Erza always wore the necklace until the next time she was able to see her. Everynight Erza would pray that one day she will be able to see you and hear you. She constantly thinks about you and thinks to herself ' you didn't have to give up your life.. we could've gotten through this together like we always do.. '