Obviously, Yugi and Yami are the most popular. They are the main characters and their relationship is central to the story. Writers often like to explore their bond further, whether it's in a more emotional or action - packed way.
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.
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.
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.
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.
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 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.
First, study the original material about dimensions. Understand the basic concepts, the rules that govern them, and the existing characters. This knowledge will be the foundation for your fanfiction.
One reason is the unique world - building. In 'dark side of dimensions fanfiction', writers can expand on the already rich concept of dimensions in ways the original might not have. They can introduce new rules, strange creatures, and uncharted areas of these dimensions. It gives a sense of mystery and discovery that readers find appealing.