Another plot might be that Natsu is injured as a result of some sort of betrayal within his guild. He has to not only recover from his physical wounds but also deal with the emotional pain of being betrayed. His friends then have to prove their loyalty and help him regain his trust in the guild.
One possible plot could be that Natsu gets hurt during a battle with a powerful dark mage. His friends then have to find a way to heal him while also dealing with the threat of the mage still being around. Maybe they search for a rare magical herb or seek help from a reclusive healer.
One possible reason could be a misunderstanding during a mission. Maybe Erza's actions were misinterpreted by Natsu, leading to him getting hurt, either physically or emotionally.
Well, there are several potential plots for this kind of fanfiction. Maybe Natsu is in an environment where he is constantly bullied and abused, like in a guild where some members are jealous of his power. Lucy, who has a kind heart, decides to take him under her wing. She might teach him self - defense or help him build his self - esteem. Another plot could involve Natsu being abused due to a family secret or a prophecy that makes others target him. Lucy, with her intelligence and courage, tries to rewrite the fate that seems to doom Natsu to abuse. This could involve going on quests to find artifacts or information that can change the situation.
One possible plot could be that Natsu discovers a magic that allows him to sing and this singing has an effect on a snow fairy. Maybe his song can heal the snow fairy or break a curse on it.
Perhaps in the fanfiction, Natsu is betrayed by someone he trusts in a mission. For example, they might leave him behind in a dangerous situation to fend for himself while they take the credit for the mission. Or it could be that a love interest betrays Natsu by choosing someone else over him due to some false perception or external pressure.
One possible plot could be that during a dangerous wizarding battle, Hermione gets hit by a dark spell and her friends, like Harry and Ron, have to find a way to reverse the spell's effects. Another plot might involve Hermione being poisoned accidentally in the Hogwarts kitchens while researching a new potion, and she has to fight for her life as the school's medical staff tries to find an antidote.
One possible plot could be that the BTS members notice a hurt staff member backstage during a concert. They then stop what they're doing to help the staff, showing their kind and caring nature. For example, they might call for medical help or offer words of comfort.
Well, in some fanfictions, it could be that Lucy is under a curse. This curse makes her act out of character and she ends up hurting Natsu. Maybe she is cursed to attack the closest person to her, and at that moment, it's Natsu. Or it could be a situation where Lucy is forced to choose between saving herself and Natsu in a dangerous situation, and her choice, even if it's to save herself, could be seen as hurting Natsu. Also, there could be a plot where Lucy is brainwashed by an enemy who wants to break the bond between her and Natsu, and as a result, she causes him harm.
One possible plot could be that Toby gets physically hurt during a mission or an encounter with an enemy. Maybe he's protecting someone and takes a blow that leaves him injured. Another could be that he gets hurt emotionally, like being betrayed by a friend or someone he trusts, which leads to his internal pain and struggle.
He might have to withdraw from the games, which could greatly impact his team's chances of winning.
One possible plot could be that Natsu sacrifices himself to save his friends from a powerful dark magic. He might use all his power to defeat an ultimate evil, but in doing so, it drains his life force. Another plot could be a tragic accident during a mission where Natsu is caught in a powerful spell that he can't escape from and it ultimately takes his life. And perhaps there could be a situation where he is poisoned by a very rare and deadly substance that no one can cure in time.