Another character could be a rival. This rival might be jealous of Harry getting all the attention while singing 'Welcome to My Life'. This could create some conflict in the fanfic, with the rival trying to undermine Harry during or after his performance.
There could be his best friends, like Ron and Hermione. They might be in the audience when Harry sings, and their reactions could be an important part of the story. Maybe they're proud of him, or they're moved by the lyrics because they've also been through a lot together.
There could also be a mentor figure, like Dumbledore. He might be the one who encouraged Harry to sing the song as a form of therapy or self - expression. Dumbledore could be in the background, observing Harry with a knowing smile, understanding the deeper meaning behind Harry's choice of song.
The plot could be about Harry using the song 'Welcome to My Life' to express his personal journey in the fanfic world. Maybe he's had a tough time fitting in, and through singing this song, he finds connection with other characters who have similar experiences.
Another character could be a fellow inmate who has been in jail for a long time. He befriends Harry and teaches him the ropes of surviving in jail.
A group of misfit soldiers could be main characters too. They are all a bit different and don't quite fit the typical military mold. But together with Harry, they form a unique unit. There might also be a high - ranking officer who takes an interest in Harry's progress and either helps or hinders him depending on the situation.
Dumbledore could also be an important character. He might be the one who tries to figure out what's wrong with Harry and tries to reverse this hatred. Another character could be Snape. He might see this as an opportunity to make Harry's life even more difficult or, on the other hand, might be secretly trying to help him get over this hatred.
The members of Wildwind would surely be important characters. They could interact with Harry, maybe give him backstage passes or even ask him for his opinion on their new songs.
His friends like Sasuke, Sakura, and Kakashi could be the audience. They would be really surprised to hear Naruto sing such a song and it could lead to some interesting conversations about their own lives and the hardships they've been through.
It could also be an experienced fanfic writer who has written many stories in the Harry Potter fandom. They might have seen the potential for an interesting dynamic in Harry singing to Severus and decided to bring it to life in their writing. Maybe they were inspired by a particular scene in the original books or movies where Harry and Severus had an intense moment that could be expanded on with this singing scenario.
Hermione would be a great addition. Her thirst for knowledge and love of books would make her very interested in alchemy. She could help Harry decipher the complex alchemical texts. Also, Professor Snape could be involved. Given his expertise in potions, he might have some knowledge or interest in alchemy that could either help or hinder Harry's alchemical journey.
There could be his drill sergeant, a tough but fair character who helps shape Harry into a good air force member. Maybe a fellow recruit named Tom who becomes his best friend and they support each other throughout their training.
Well, Dumbledore would most likely be a significant character. He might be one of the few people who quickly understand the implications of Harry being a mutant. He could help Harry navigate through the challenges that come with his new identity. Additionally, there could be some mutant characters from the mutant universe who cross over into the Harry Potter world. For example, a character like Professor X could be an interesting addition, guiding Harry in understanding and using his mutant powers in a responsible way.