I'm really sorry for the long wait, everyone. But I just can't think of a way to write the Grand Magic Games Arc since I'm not placing Leora into the game. So, you can say almost all the parts of the story will almost be the same as the original story.
And, I decided to skip most parts. Again, I'm sorry.
As Lucy tried to close the Eclipse Gate with Yukino, seven dragons had managed to pass through the gate before they successfully closed it. future Rogue arrived and proclaimed that the number of dragons present was enough for him, declaring to all that the era of Dragons was about to begin. He then ordered the dragons to eliminate all the Mages in Crocus, commanding them by means of his Dragon Supremacy Magic which forced the dragons to obey him, including Zirconis. Despite every guilds' attempts in attacking the dragons, the mages were able to inflict little damage, making them doubt their chances of victory. Thus, future Rogue joyfully told the dragons to show their wrath.
Leora ran towards Sabertooth to find Sting and Rogue. When she found them, she stunned the dragon they were attacking with lightning magic before dropping down in front of Sting and Rogue. "Sting, Rogue. Blast me with your magic." said Leora. "What?! Are you insane?!" yelled Sting, shocked. "We need all the energy we have to take down the dragons." stated Rogue. "Just a small blast. Trust me." said Leora with determination. With the look from Leora, Sting and Rogue couldn't help but obliged.
At the far side of the battle, Doranbolt returned from afar, heavily exhausted after having brought Cobra from prison to assist in the battle after having been forced to ask for his assistance. "As much as it pains us... We need you help..." said Doranbolt as he panted. "I can hear it all, Natsu." said Cobra.
"You're Cobra, the poison dragon slayer right?" said Leora as she appeared in front of them. "I want you to blast me." "This is no time for a fight!" yelled Lahar. "I'm serious. I'm doing this to protect my family." said Leora. Cobra did Poison Dragon's Roar and aimed it at Leora, to which she just sucked in all the magic. After he did what he needed, Cobra left to fight the dragons.
Leora dropped to her knees as Cobra left, feeling all seven magic inside her body. "Hey, are you okay?" asked Doranbolt, after witnessing the scene. "It just hurts a little. Go, away from me, to save them." said Leora. "I'll be in top shape in a moment." Doranbolt looked at Lahar, who nodded in return, bringing all the soldiers into the battlefield.
As the battles raged across Crocus, things seemed to be going badly for the Mages, with not only Gray being killed, but Bacchus and Droy receiving fatal wounds, and Macao being pinned down by Motherglare's hatchlings. Elsewhere amongst the rubble, Ultear grieved over her sins, and was ashamed of herself despite Gray granting her a second chance in life. She then recalled when she was learning her Magic, the Arc of Time, and how she came upon a spell that reverses time, known as Last Ages. Back then, Hades advised her to never use the spell, since the cost of reversing the time of everyone in the world would be her life. In the present, in order to make up for all the evil she had committed in the past, she chose to use the forbidden spell, hoping to at least reverse time to before the Eclipse Gate was opened.
Ultear cast the spell, causing her entire body to get horribly burnt in the process. After the spell's completion, with the last of her strength, she turned to look at a clock to find that she had only turned back time by one minute. As she fell, she wondered if that is really all her life is worth and lamented at how she was unable to save a single life. In the new 'present', back at the ruins of Bar Sun, just as Gray saved Juvia from an attack from a hatchling, they, plus Meredy and Lyon, viewed a glimpse of the future in which Gray died. At first confused, they are surprised as the events they just saw occur again right in front of them, though they managed to counter the attack this time. As people all over the world saw a minute into the future and puzzled over what happened before going on with their daily lives, the Mages in the life and death battles in Crocus were able to use that knowledge for a counterattack. Some, like Jet, Droy, Macao, Wakabe and Romeo, moved from their current location in order to avoid casualties, while others, like Bacchus and all the Dragon Slayers, used that knowledge to fight back.
Just then, all the dragons that were on the ground were hit by a punch or a kick to the head. The attacker landed on a tall building and let out a ferocious roar, calling all the dragons in. All the dragons headed towards the building to see their attacker. All of their eyes widen. Their attacker was none other than Leora. Her hair has 7 different colours on her bangs. "What are you doing here?!" yelled Scissor Runner. "I live here!" yelled Leora, her pupil as sharp as a dragon's. "Stop all this right now! Go back to your time!" "No can do, little princess. I want to eat some tasty humans." said Zirconis. "We are forced to obey the one called Rogue." said the Rock Dragon. "If it's a fight you want, it's a fight you'll get." said Leora as black and gold scales covered her skin. "Natsu will be done with him soon."
All the dragons used their roar attacks on Leora at once. Leora jumped and evaded their attack and landed on top of the Rock Dragons head. "You are not getting anywhere near Wendy." said Leora as she looked directly at Zirconis before releasing a roar containing all the seven magic she have in her body. The other dragon slayers were all occupied by the miniature dragons. Leora continued to battle all five dragons by herself using dragon's roar, dragon's claw and dragon's fist.
Finally, Natsu delivered the finishing blow on the future Rogue and sent them and the dragons crashing into the Eclipse Gate, destroying it in the process. With the Gate finally broken, those present witnessed the dragons and future Rogue's bodies glowed, as they started to return to their own time. As threats disappeared, almost all of the Mages rejoiced, having won the battle. The exception being Mavis and the dragon slayers, excluding Leora, having realized that none of them actually managed to beat their Dragon opponent.
Sorry for it being short. I literally have no idea on how to make it longer.