Well, it could be that the very magic that Atem uses to try and combat the Dark Side of Dimensions is actually fueling it in some way. He might find out that every time he casts a spell or uses his powers, it's making the situation worse. And then he has to figure out a completely new way to deal with the threat, which could involve sacrificing some of his own power or making a deal with an unlikely ally from the Dark Side of Dimensions.
One of the most interesting plot twists could be Atem facing a new, more powerful enemy from the Dark Side of Dimensions that he thought was long gone. Maybe an ancient evil that was sealed away and is now unleashed due to some disruption in the spirit world. Another could be that his friends in the real world are in danger in ways he couldn't have predicted, like being possessed by dark entities from the other dimension.
Perhaps a plot twist could be that Atem discovers that his connection to the Dark Side of Dimensions is not what he thought. Instead of being just a threat to overcome, it turns out that there is a part of him that is linked to it in a more complex way. For example, his past actions in the spirit world might have unknowingly contributed to the current chaos in the Dark Side of Dimensions. This would force him to re - evaluate his entire understanding of himself and his role in both worlds.
Atem's character might develop by becoming more cautious. After all, the Dark Side of Dimensions is full of unknown threats. He could start to think more before taking action as he realizes the potential consequences of his actions on both his world and the spirit world.
A really interesting plot twist would be if Harry Potter was somehow transported to Gotham as a child and raised there. He would grow up with a different set of values and skills, and when he discovers his magical abilities later on, he has to balance his newfound magic with the street - smart tactics he learned in Gotham. This would completely change his character and how he approaches the fight against Voldemort. And when Batman eventually meets him, he's not the typical Harry Potter we know from the books. It could lead to a whole new dynamic between them.
A possible plot could involve Revan and Bastila delving deep into the dark side teachings. They might discover long - lost Sith techniques and use them to gain power. As they grow in power, they attract the attention of other dark side entities. This could lead to power struggles, alliances, and betrayals within the dark side community. Their relationship could also evolve in complex ways as they are influenced by the dark side, perhaps from a partnership to a more competitive or even a possessive one.
Perhaps the character is reborn with memories of a future event that threatens the Mikaelsons. This would put them in a position to either try to change the future or use it to their advantage within the family dynamics. They might face disbelief from the Mikaelsons at first, but as events start to unfold as they remembered, they gain more influence.
Perhaps there is a plot point where the relationship between Kaiba and Anzu changes in a significant way. Maybe they have to rely on each other more than they ever did before, leading to a deeper understanding of one another.
Another angle could be the creative liberties taken by the author. Fanfictions often deviate from the original story to some extent. In this case, the author might have added unique plot twists, new characters related to Kaiba and Anzu, or different power dynamics that make the story stand out from the official 'Kaiba and Anzu' narrative.
One possible plot twist could be that Harry, under the influence of the dark side, forms an alliance with Bellatrix against the Order of the Phoenix. Maybe he discovers some dark secrets about his parents that lead him to question his previous beliefs and side with her.
In some fanfics, a plot twist could be that Severus was actually protecting Hermione all along under Dumbledore's secret orders, and Sirius discovers this and has to re - evaluate his hatred for Severus. This completely changes the dynamic between the three.
One interesting plot twist could be that Naruto starts to have memories of Tobirama's past battles. This would make him question his own identity and purpose. Another could be that Tobirama's reincarnation in Naruto causes a shift in the power dynamics among the villages. It might make other villages see Konoha as a greater threat or as a source of new knowledge.
One of the most interesting plot twists could be that Naruto discovers a new form of chakra that has the power to rewrite history. This would completely change the power dynamics in the Naruto universe.