It could be that the fanfiction has a plot point where they discover something unexpected about the Dark Side of Dimensions, like a hidden power or a long - lost secret that changes the course of their journey and their perception of this strange realm.
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.
A cool plot could be that there is a time - traveling aspect. A new villain travels back in time to change the events of 'Dark Side of Dimensions' in order to gain ultimate power. Yugi and his friends then have to follow the villain back in time and stop them. This would involve them having to navigate the past, deal with younger versions of themselves and their friends, and make sure that history doesn't get completely rewritten in a way that destroys their present world.
One idea could be exploring the backstories of the minor characters in the movie more deeply. For example, you could write about how a certain duelist got to where they are in the Dark Side of Dimensions world. Another idea is to create an alternate ending where the main conflict is resolved in a different way, perhaps with a more complex strategy during the final duel.
Well, the story mainly focuses on the return of an old foe. Yugi and the gang are drawn into a series of events that lead them to discover more about the Dark Side of Dimensions. This includes new and powerful cards, and duels that test their skills like never before. There are also elements of mystery and a struggle to maintain balance in the world of Duel Monsters.
One possibility is that it delves deeper into the mysteries that were left unsolved in the movie. It could explore the origin of some of the powerful cards or the true nature of the dark forces that were hinted at. The fanfiction might also introduce new characters who are related to the existing ones, like a long - lost relative of Kaiba who has some secrets about the Millennium Items.
Since I don't have access to this fanfiction, it's hard to say for certain. However, if we think about common themes in similar stories, Anzu might be struggling against Marik's dark side in a battle of wills. Maybe she has to make difficult choices that will either save herself and others from Marik's dark half or risk being consumed by it. It could also involve her trying to understand the root of Marik's dark transformation and using that knowledge to her advantage.
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.
One idea could be exploring an alternate ending where Yugi and Yami have to face a new threat in the Dark Side of Dimensions that was hidden all along. Another could be a story about their friendship growing even deeper during an adventure in that dimension. Maybe a fanfiction where they meet new characters who have unique powers and they have to team up with them to save both worlds.
Well, one possible development could be Kaiba's initial shock and disbelief. He might think Anzu is lying or has some ulterior motive at first. Then, he could start to come around and consider how this will change his life and his relationship with Anzu. Maybe he'll become more protective of her.
One common theme could be the exploration of the complex relationship between the characters involved in the Prideshipping. It might also touch on the darker aspects of their personalities as hinted by 'Dark Side of Dimensions'. Another theme could be adventure, with the characters embarking on quests or facing challenges within the context of this fan - made universe.