Another plot twist could be that the female dragon and the male reader have met before in a past life. They were lovers in that life but something tragic happened. Now, in this life, they are drawn to each other again but there are forces that don't want them to be together. This adds a layer of mystery and a fight against fate to their relationship.
Another plot twist could be that the male reader has a hidden power that only the female Lucario can unlock. But in the process of unlocking it, he loses his memory of her, and she has to find a way to make him remember their relationship and the power within him.
A plot twist could be that Kankuro's past comes back to haunt him. Maybe he had made an enemy long ago and now that enemy targets the reader to get back at Kankuro. This forces Kankuro to face his past and also makes the reader see a more vulnerable side of him. Or perhaps the reader discovers a secret about Kankuro's puppets that changes their perception of him for a while. They have to work through this new information and their feelings for each other.
One possible plot twist could be that the reader discovers Negan has a secret mission that would put their group in danger. This creates a huge conflict between their love and loyalty to their own people. Another twist might be that Negan has an old enemy who targets the reader to get back at him, forcing Negan to make some tough choices to keep the reader safe.
One plot twist could be that the heartless, which was initially seen as the one with the vore - like power, turns out to be a victim of a greater vore - related force. And the kh reader has to save it.
A plot twist in a minato x reader love story might be that Minato loses his memory. He forgets all about the reader and their relationship. The reader has to then try to make him remember their love all over again. Or perhaps there is a false accusation against the reader that makes Minato question their relationship. He has to decide whether to believe in the reader or the rumors.
One possible plot twist could be that Judal is forced to choose between his loyalty to someone or something else and his love for the reader. Another might be that the reader discovers a dark secret about Judal that makes them question their relationship. Maybe the reader has a hidden power or identity that Judal initially doesn't know about, and when it's revealed, it changes the dynamics of their love story.
A plot could involve the male reader being in a situation where he has to protect the female SCP 1471 from other, more hostile SCPs. As they flee together, they learn about each other's strengths and weaknesses. Or perhaps the male reader stumbles upon a way to communicate with SCP 1471 on a deeper level than anyone else has before. This could lead to a story where they work together to uncover secrets about the SCP Foundation itself.
One interesting plot twist could be that when Natsu turns into a dragon, he loses his memory of his human friends. This would create a lot of drama as his friends try to bring back the Natsu they know. Another could be that he turns into a different kind of dragon than expected, perhaps one with a very rare and powerful ability that attracts the wrong kind of attention from dark forces in the fanfiction world. And also, he might transform into a dragon at a crucial moment during a battle, not only surprising his enemies but also his allies, changing the whole dynamic of the fight.
One common plot twist could be Issei's sudden loss of control over his Dragon God powers. This can create a lot of chaos and internal conflict for him as he tries to regain control and not harm those around him.
Another plot twist could be that the reader has some sort of power or knowledge that Loki needs. So, instead of a malicious kidnapping, it's more of a strategic move on Loki's part. He might be trying to bargain with the reader to get what he wants, but as time passes, he starts to develop feelings for the reader.