What are some possible plotlines in a 'Deku Turns into an Adult' fanfiction?

A new villain could emerge who is specifically targeting adult heroes. Since Deku has now become an adult, he becomes a prime target. This villain might have a grudge against the hero society's adult leadership and see Deku as a symbol of that.

Perhaps they get involved in a power struggle within the villain world. They want to prove themselves as the most feared villains. This could lead to battles with other villains and alliances with some unexpected characters. It could also involve them trying to steal some powerful artifacts or secrets from the hero side to gain an edge in their villainous activities.

Another plotline could involve a betrayal within the group that causes Elsword to turn dark. For example, if he discovers that one of his closest allies has been secretly working against him all along, the shock and anger could drive him to the dark side. He might then start to seek revenge on not only the betrayer but also those he perceives as being part of the conspiracy.

A plotline could involve Zelretch having a specific reason for turning Shirou female. It could be part of a grand plan to save the world or to correct some imbalance in the magical realm. And as Shirou is now female, she may discover new magical abilities or limitations that come with her new form. This could lead to a whole new adventure as she tries to master these changes while dealing with the overarching plot.

In a 'Tails Turns into a Robot' fanfiction, it could be that an ancient technology is accidentally activated by Tails. This technology fuses with him and turns him into a robot. He then discovers that he has a special connection to an ancient robotic civilization. He has to navigate his new identity, learn about this civilization, and decide whether to embrace his robotic self or try to find a way back to his normal form all while facing challenges from those who fear or want to use his new - found powers.

One possible plotline could be that the boy, after turning into Black Widow, has to adapt to her skills and abilities. He might find himself in the middle of a spy mission and has to use her combat and espionage training to get out of sticky situations. Another could be that he has to deal with the memories and emotions that come with becoming Black Widow, like her past traumas and relationships.

One possible plotline could be that Harry discovers a dark secret about his family and feels betrayed by the wizarding world. This could lead him to side with the dark forces. Another could be that he is influenced by a powerful dark wizard who manipulates his mind. Maybe he becomes envious of the power others hold and decides to take it by any means, turning evil in the process.

Maybe Harry discovers some dark family secrets that make him question his place on the 'good' side. He could find out that his ancestors had strong ties to dark magic, and this knowledge could slowly corrupt him. He might start to experiment with dark spells, thinking that he can control them and use them for what he believes is the greater good, but gradually slips towards the darkside.

Well, in this fanfiction, if Ash turns into Pikachu, it might lead to a story where Pikachu - Ash discovers new aspects of the Pokémon world. For example, he could experience the world from a Pokémon's perspective, understanding their fears and joys more deeply. He might also have to deal with other Pokémon who don't immediately recognize him as Ash and react in different ways to this strange Pikachu.