A plot twist could be that the character turned into a slime starts to lose their memories, but as they adapt to their new form, they start to regain them in a different way. This could lead to revelations about their past or a greater mystery. Or perhaps the slime form is not permanent, and there are certain conditions for reverting back. But when the time comes to change back, the character has to make a difficult choice because they've grown attached to their slime abilities. Maybe the slime form is part of an experiment by a mad scientist, and the character has to find a way to break free from the scientist's control while still in slime form.
First, give your character a distinct personality even in slime form. For example, if they were a brave hero before, they could be a fearless slime that doesn't back down from challenges. Second, show their struggle with the transformation. They might be disgusted at first or confused about their new body. Third, let their relationships with other characters evolve. Old friends might be repulsed, and new allies could be made among slime - related creatures. This creates interesting dynamics.
Well, often in these fanfictions, a plot twist is that Sehun, as a vampire, has a connection to an ancient vampire prophecy. This prophecy could be about saving the vampire race or bringing about a new era. Another plot twist could be that he gets hunted by vampire hunters who are actually his old friends or acquaintances from his pre - vampire days. And one more could be that his vampire transformation is not complete, and he has to go through a series of trials to fully become a vampire or to regain his humanity.
Well, a great plot twist could be that Percy is turned into a vampire but he was actually part of an ancient prophecy in the vampire world. As he struggles to adapt to his new life, he finds out that there are vampire hunters who are after him not just because he's a vampire, but because they believe he will bring about a great change in the vampire - human balance. Also, his transformation could be different from other vampires. Instead of craving blood right away, he has a strange attraction to something else, like the essence of magic, which is very un - vampire - like and causes confusion among the vampire clans.
One interesting plot twist is when Rimuru starts to build his own nation. It's unexpected as he was just a slime trying to survive at first. He manages to gather various races under his leadership, which changes the whole dynamic of the story.
One possible plot twist could be that Issei, now a girl, has to navigate the world of relationships in a completely different way. For example, she might find that her male friends treat her differently, and she has to re - evaluate her friendships. Maybe she'll also have new romantic interests from unexpected sources, like a girl who used to be just a friend now seeing her in a new light. Another plot twist could be related to her powers. If in the original story Issei had certain male - related powers, as a girl they could either change in nature or she could struggle to control them in the same way, leading to some interesting challenges and growth.
In this type of fanfiction, an interesting plot twist might be that Harry, as a girl, is underestimated by many of the male characters at first. But then she uses this to her advantage. She could pretend to be meek and mild while secretly gathering information and planning strategies. Also, her transformation could lead to a change in the way Hogwarts is run. Maybe she starts a movement for more equality between male and female students, which causes a stir among the old - fashioned teachers.
One interesting plot twist could be that Sakura, as a cat, discovers she can communicate with other animals and they lead her to a hidden magical place. This place holds the key to turning her back into a human but also reveals a dark secret about why she was turned into a cat in the first place.
One of the interesting plot twists is when Rimuru Tempest, the slime, manages to assimilate the unique skills of other creatures. It completely changes the power dynamics and his capabilities in the story.
Another interesting plot twist is when an unexpected guest shows up at the wedding. Maybe an old flame of one of them comes and tries to stop the wedding. This causes a stir among the guests and makes Klaine re - evaluate their relationship briefly. But of course, in the end, they realize their love is stronger than any interference.
Perhaps in the fanfiction, when time is turned back, Hermione decides to focus on different areas of magic. Instead of being all about books and rules, she starts to explore dark magic in order to stop Voldemort before he rises. This could put her at odds with Harry and Ron. Also, if time is turned back far enough, Dumbledore could be a student again. He might make different choices that change the whole wizarding world's future, like not getting involved with Grindelwald, which would have a huge impact on the events leading to Voldemort's rise.