I don't own Justice League or Fairy Tail just any OCs I may throw in and unlike in the prequel so far nothing from the Harry Potter series will be there just mentioned. Justice League shouldn't play any part after Mass Extinction arrives on Earthland.
As everyone readies to attack the crystals, Natsu and Zero clash: the latter's Genesis Zero seems to overwhelm Natsu, but Natsu manages to literally devour it using the golden flames he was granted, and then reveals an astonished Zero the true power of a Dragon Slayer, roaring out loudly as the image of an imposing Dragon appears behind him. He proceeds to hit Zero, and finishes Oración Seis' leader off with his Crimson Lotus: Phoenix Blade, sending him crashing through the Lacrima crystal just as his comrades attack theirs, thus destroying Nirvana.
Following the destruction of the Lacrima crystals, Nirvana starts to fall apart, and everyone tries to make it outside. Wendy and Carla and are saved by Jura, Natsu and Jellal by Hoteye. With everyone safe, the gathered group is introduced Jellal and told that he lost his memory; despite his past, evil deeds, having helped them out, he's considered a friend. During a private conversation, Erza and Jellal reconcile, with the woman telling him that she'll be at his side to help him while he gets back his memories, and Erza tries to add something, but is interrupted by the arrival of the Council's 4th Custody Enforcement Unit, led by Lahar. The man explains that the Council has now been restored, and that they are here to capture certain criminals.
The army starts with Hoteye, for his past sins as an Oración Seis member, despite him having being turned good by Nirvana. Jura tries to speak against them, but Hoteye decides to be arrested since he can never be rid of his sins even if he turned good. Before he gets taken away, Jura tells him that he will continue the search for his younger brother in his place, and asks for his name. Hoteye says his name is Wally Buchanan, and Erza, surprised, instantly tells them that she knows him and that he is alive and well, traveling across the continent with his good friends. This makes Hoteye burst into tears, and realize that there is hope for those who believe in the light. He is taken into custody with no regrets or worries.
Lahar proceeds to tell them that they are after another person, even more dangerous than the Oración Seis: Jellal. For his crimes of infiltrating and destroying the Council, as well as firing Etherion, he's to be arrested.[60] Wendy tries to convince Lahar to change his mind and protests that Jellal could not even remember what he did, but Lahar refuses, and says ignorance of one's crimes is no excuse and that Jellal will either receive execution or life imprisonment. Jellal remains calm, accepting his punishment and thanking Erza for everything she has done. Erza looks on helplessly as her long-lost friend is about to be taken away from her permanently just after reuniting. As she thinks that she can't let Jellal go, Natsu attacks the soldiers, saying he won't allow Jellal to be taken away since Jellal is one of them now. Natsu tells Jellal that he has to stay by Erza's side for her sake, much to Jellal's distress, with his new friends exposing themselves and risking their freedom for him, who's resigned to turn himself in. Just as Lahar orders his underlings to arrest them all, after making a terribly difficult decision, Erza cries for them to stop, stating she'll take responsibility herself, and tells them that they can take Jellal away, much to his relief. Before being taken into custody, Jellal manages to remember one final thing, Erza's surname, Scarlet, stemming from her hair, and openly tells it before bidding farewell to Erza, with her sadly saying the same.
Following Hoteye and Jellal's arrest, the group feels dejected, and Erza is shown sitting alone. She remembers her slave days, when, due to her not having a surname, Jellal came up with Scarlet, due to the color of her hair, and says he will never forget her name. She bursts into massive tears, and pronouncing Jellal's name, starts crying desperately, watching the incoming sunrise bearing the same color as her hair.
Joining the friends that were on the Christina and arriving at Cait Shelter, everyone gets new clothes to restore their torn up ones. They meet up with the people of the Guild, and, after receiving their sincere thanks from Roubaul, the most exuberant members of Team Light try to celebrate, but then notice Roubaul upset. Cait Shelter's Master goes on to explain that they are not, in fact, the descendants of the Nirvit, but the Nirvit tribe itself. He explains that 400 years ago he was the one who created Nirvana to stop the wars raging throughout the country, and founded a village on the machine itself, which enjoyed a time of prosperity. However the darkness that they removed from the targets found its way to the Nirvit tribe itself, and made the people kill everyone in cold blood, with only Roubaul managing to escape and eventually dying, just to live on as a spirit. He sealed Nirvana away, since he couldn't destroy it himself, and settled in an abandoned town to watch over the machine until someone could destroy it. He swore and remained in solitude for some time, until a child with Jellal's appearance appeared carrying an unconscious Wendy, asking him to take care of her, to which Roubaul agreed. Wendy then woke up and asked where she was, since her companion told her that he was going to take her to a guild. Roubaul, not wanting Wendy to feel sad, said that the place was, in fact, a guild, and used his extremely powerful Magic to turn the wrecked town into a guild and create illusory people to be part of it.
Now that the burden of Nirvana is destroyed, the guild members start to disappear, and, as Wendy, in despair, is told by Roubaul that she no longer needs illusory companions, having found real ones. As Roubaul himself, his task completed, starts disappearing, Wendy runs towards him, but he vanishes before she can reach him, telling her that's just the beginning and that the future awaits her, thanking her newly-acquired comrades and asking them to look after her and Carla.
Her Cait Shelter mark gone from her arm, Wendy desperately cries out for Roubaul with tears in her eyes, as everyone else stare on silently. Erza nears Wendy and kneels behind her, telling her that she knows it's hard to have someone close disappear, but that her comrades will help her bear that sadness. She then invites her back with them to Fairy Tail.
The group from Fairy Tail, alongside the new entries Wendy and Carla, sails back towards their Guild, having parted with their friends from the Allied Forces. Lucy has obtained Angel's three Gold keys, Gemini, Scorpio and Aries and her Silver key Caelum, favorably impressed by her kind attitude towards Celestial Spirits. The group reaches Fairy Tail, were they are welcomed back, with great excitement about Wendy and her Dragon Slayer Magic which shocked them at first. A great party is organized for the occasion, and everyone is happy. While his guildmates celebrate, Mystogan is briefly shown glancing at them before disappearing. A few days later, Fairy Tail is in turmoil: much to everyone's excitement and happiness, Fairy Tail's strongest Mage, Gildarts Clive, will return, having been away three years on a mission which nobody could complete in 100 years.