Archive of Our Own (AO3) is also a great place to look for kaiba x mokuba fanfiction. It has a wide variety of works, and the tagging system makes it easy to filter out exactly what you're looking for. Some stories might be more focused on their relationship development, while others could be adventure - based with their relationship as a backdrop.
One good kaiba x mokuba fanfiction could be 'The Bond Beyond Brothers'. It focuses on their strong relationship and how they support each other through various challenges in the Yu - Gi - Oh! universe.
The Blue - Eyes White Dragon could be an unexpected rescuer. In some fanfictions, the powerful card could come to life or have a spiritual connection to the Kaiba family. Also, an undercover detective who has been investigating the Kaiba family's enemies might be the one to rescue Mokuba. This detective could have been on the trail of the kidnappers for a while. And lastly, an old family friend or mentor of the Kaibas could emerge to save Mokuba. This person might have some special knowledge or skills that are crucial for the rescue operation.
Another theme could be adventure. Since Yu - Gi - Oh! has elements of adventure and dueling, the OC and Mokuba might go on adventures together, whether it's exploring a new dueling tournament or uncovering some mystery in the Yu - Gi - Oh! world. This theme allows for a lot of action and character development within the fanfiction.
A possible plot twist is that the kidnapper is being controlled by an otherworldly force, and Mokuba discovers a way to break the control. For example, he might find a magical item within the kidnapping location. Another plot twist could be that Mokuba's kidnapping was part of a bigger scheme to frame Seto Kaiba for a crime he didn't commit. This would add a layer of drama as Seto has to race against time to clear his name and save his brother. Also, it could be that the kidnapper is actually Mokuba's long - lost relative who wants to reconnect in a very extreme way.
You can try fanfiction websites like Archive of Our Own (AO3). It has a large collection of fanfictions, and you can search for 'Mokuba Kaiba x OC' specifically. There are often filters to sort by popularity, rating, etc.
In the fanfiction, Mokuba may come across some lesser - known students at Duel Academy as well. These students could have unique dueling styles or backstories. Maybe there's a shy student who Mokuba befriends and helps gain confidence in their dueling abilities.
The abuse from Gozaburo could lead Seto to have a more complex view of power. He may start to see power not just as a means to an end, but also as something that can be misused. This realization could make him more careful in his own pursuit of power and more empathetic towards those who are powerless, which is a significant shift in his character.
One common theme is family. Their brotherly bond is often explored deeply. Another is growth, like Mokuba growing up under Seto's guidance. Protection is also a big theme, with Seto being very protective of Mokuba.
Characteristics of yugi x mokuba fanfiction include their shared growth. As the story progresses, they both learn and develop as characters, often because of their relationship with each other. There's also a sense of protection. Yugi might protect Mokuba or vice versa, and this protective instinct is often explored. Moreover, the fanfictions can have a lot of cultural elements from the Yu - Gi - Oh! series, such as the importance of cards and the rules of dueling, which are intertwined with their relationship story.