A story could be written where Rias and Akeno take a trip together to a new and unfamiliar place in the underworld. During this journey, they encounter different cultures and customs among devils. As they experience these new things together, they learn more about each other's likes and dislikes, and their relationship evolves on a more personal level. They might also have to rely on each other for survival in this strange new environment.
One way is to introduce a new character who causes some sort of rift between them at first. Maybe a new devil who tries to drive a wedge between Rias and Akeno by spreading false rumors. But then, as they figure out the truth together, they become even closer than before. It would be a journey of trust - building and forgiveness that would enhance their relationship.
In Highschool DxD fanfiction, Rias and Akeno have a very complex and interesting relationship. They are both important characters in the series. Rias is the powerful devil princess, and Akeno is her loyal follower and friend. In many fanfictions, their bond is explored deeper, showing their mutual respect and how they support each other in different situations, like in battles against other devils or in dealing with the complex social structure of the devil world.
The dynamic between Rias and Akeno in Highschool DxD fanfiction is really captivating. Akeno is always by Rias' side, whether it's in school or in devil - related matters. They have a strong bond that is based on trust and mutual understanding. Rias, being the leader, often relies on Akeno's advice, and Akeno looks up to Rias as her role model.
Their relationship could develop further through shared challenges. For instance, if they face a really tough opponent together, they'll learn more about each other's strengths and weaknesses, and that can deepen their bond. Another way is through communication. If Issei starts to open up more about his insecurities and Rias does the same, they can become closer on an emotional level.
Their relationship could be developed uniquely by having them swap bodies for a while. This would force them to see things from each other's perspective. Issei would understand the pressures Rias faces as a devil princess, and Rias would get a taste of Issei's more carefree but determined human side.
The human OC can be developed by giving them unique abilities. For instance, they could have a special power that Rias doesn't have or understand. This would make them stand out and be a threat to Rias. Another way is through their backstory. A tragic or interesting backstory can make the readers sympathize with the OC and understand their motives for bashing Rias.
One way is to explore her family background more. For example, showing how her upbringing in the devil society influenced her leadership style in the student council.
One way to develop her character is to have her learn new skills. For instance, she could start training in martial arts or some form of magic that is accessible to humans in the Highschool DxD world. As she learns, she could face setbacks and challenges that force her to grow both as a fighter and as a person.
Tiamat could be developed further by exploring her relationships with other characters. For instance, if she starts to mentor a young character, it would show a different side of her. She could teach them about her powers and the history of her kind.
For the OC, you can start by giving them a unique backstory. For example, if they had a tough childhood in the human world before being thrust into the supernatural world of Highschool DxD, it could make them more reserved yet determined. Akeno, on the other hand, is known for her alluring and mysterious nature. You could develop her personality further by showing her more vulnerable side when she's with the OC, like how she might open up about her own past traumas.
Another way to develop their characters is to put them in a situation where they have to make a difficult choice. For instance, they might have to choose between loyalty to their friends or following their hearts. This would force them to grow as individuals and as a pair. Their actions during this time would reveal more about their personalities and values.