If the cause of his skinniness is a magical ailment, he could search for a cure. This might involve going on a quest to find a powerful healer or a rare magical ingredient. Or, if it is due to the elf society's norms, he could try to change those norms from within. He could start a movement among the elves to promote better nutrition and a more balanced lifestyle, which would not only help him but also other skinny elves in the community.
He could befriend some other characters in the fanfiction who are more knowledgeable about elf health. They could teach him about proper diet and exercise for elves. For example, if there are elder elves who know about traditional ways to build strength and gain weight in a healthy way for elves, they could guide Harry. Also, if there is a magical spell or potion that can improve his metabolism or directly add healthy mass to his body, he could seek it out.
One way could be if he discovers a new food source. Maybe there is a magical plant or fruit that is highly nutritious and can help him gain weight. Another way could be if he finds a way to reduce the stress or overwork he is facing. If he can balance his activities, his body might start to recover and gain weight.
One possible reason could be that in the fanfiction world, elves might have a different diet or metabolism compared to other beings. Maybe the food available to Harry as an elf is scarce or not very nutritious. Another reason could be that he is overworked or constantly in a state of stress which affects his body and makes him skinny.
One way is through his physical abilities. Elves in the Lord of the Rings are known for their agility and archery skills. So, Harry could be depicted as an excellent archer, using his elven - like precision to protect his friends in the fanfiction.
It can be developed by focusing on Merlin's insecurities. For example, he might avoid certain situations like physical combat training because he's worried about being made fun of for his skinny frame. Then, through a series of events, he overcomes this fear. Maybe a new character comes to Camelot who also has a unique appearance and they bond over their differences.
In some fanfictions, a magical accident or quest can also lead to the resolution of the misunderstanding. For example, they might get trapped in a magically sealed room together. During their time there, they are forced to rely on each other and in the process, they start to communicate and realize that their misunderstandings were all in their heads.
Harry could make it up to Hermione by doing something special for her. Maybe he could find a rare book for her library in the wizarding world or help her with a project she's been struggling with. This would show her that he really cares and wants to make amends.
Well, in some fanfictions, a powerful spell might be used. For example, Hermione could find a long - lost spell in the library that is specifically designed to reverse an Animagus transformation when it goes wrong. She would then perform the spell on Harry to turn him back.
Open communication is key. Harry and Ron need to sit down and have an honest conversation about their feelings. Harry can tell Ron why he has started to lose trust, and Ron can clarify any misunderstandings.
The healer could confess their wrongdoings to a higher authority in the magical medical field, like the head of St. Mungo's. Then they could be given a set of penance tasks. These tasks might include things like working long hours in the most difficult wards, treating the most dangerous and contagious diseases without any complaint. By doing this, they would gradually earn back the trust of the community and their colleagues.
The house elf might be very grateful. Harry is known for his kindness, so the elf could see this as a chance for a better life. It might immediately start serving Harry with great enthusiasm, believing that Harry will be a fair and good master.
Natsu might need to prove through his actions that he has changed. For example, he could start being more respectful, listening to his girlfriend's feelings, and giving her space when she needs it. It would take time and effort to rebuild the relationship, but it could be possible if both are willing.