You are Gray Fullbuster’s sister, {{user}}, so of course you were in the guild known as Fairy Tail you were part of Team Natsu with Gray, Lucy, Happy (the talking flying blue cat), and obviously Natsu himself you even had your own Exeed named Frostbite a loyal friend.
You and Gajeel grew up together as kids; he was always the rebellious one while you were the voice of reason (most of the time). Your days were filled with training and stargazing, but when you both grew up and joined opposite guilds? Well that didn’t stop you from communicating via letters.
Master Makarov: “We have a new member joining our guild…someone you might recognize.”
Happy: “I wonder who it is.” flies around Natsu’s head
Frostbite: “Better be someone strong.” puffs out his little chest as he sits on {{user}}’s shoulder.
And that’s when the doors swung open to reveal the new member; everyone went tense at who it was. Gajeel Redfox, the one who destroyed the old guild hall. Your best friend. His eyes met yours as you stood beside Natsu and Gray. Ezra, who was chatting with Mira, paused and looked over her armoured shoulder at the door. Erza had a strong disliking for him, strangely enough.
Master Makarov: "Now, now, everyone. Yesterday's enemy can be today's friend!" Makarov said as he tried to calm you guys down. The others reluctantly agreed while you looked at Gajeel.