To develop Mordred in a Mordred x Highschool DxD fanfiction, her backstory can be explored further. Maybe she has some unresolved issues from her original story that resurface in the Highschool DxD setting. For instance, her complex relationship with her father figure. As she tries to come to terms with these in the new world, she could change and grow. She might also start to question her own values and beliefs as she experiences the different cultures and power dynamics in Highschool DxD, which would be an interesting way to see her character evolve over the course of the fanfiction.
Well, you could have a story where Mordred has a past connection to some of the powerful families in the Highschool DxD universe. Maybe she's on a quest to uncover something about her heritage that's linked to that world. And during her journey, she falls in love with one of the characters in an unexpected way. For example, she starts off as rivals with Rias but then they develop a deeper bond as they face challenges together.
Mordred's character development could involve her coming to terms with her identity. She can start to realize that she doesn't need to be exactly like Artoria to be worthy. She can find her own path while still respecting her connection to Artoria. For example, she could learn from Artoria's wisdom but also use her own unique approach to problems.
To write this type of fanfiction, you should focus on the relationship development. The fem OC could be from a different land, which adds an element of mystery. Research the Arthurian legends to add authenticity. For the relationship, start with a small moment of connection, like sharing a meal or a common view. Then, as they face challenges together, their bond deepens. Maybe there's a conflict where the fem OC has to choose between her loyalty to her homeland and her growing feelings for Mordred. This creates drama and keeps the readers engaged. Also, use vivid descriptions to bring the world and their relationship to life.
Sora's character can be developed by giving him relationships. For example, he could form a deep friendship with Issei. Through their interactions, Sora could learn about loyalty and friendship in the context of the Highschool DxD world. This would also allow his own values to be challenged and refined.
Yes, in some fanfictions, Merlin is written as Mordred's father. Writers often like to explore different family relationships and backstories in fanfiction, and this is one such interesting take on their relationship.
In some fanfictions, Issei might develop a more serious personality earlier on. Instead of his usual comical and pervy self from the start, he could be shown as someone with a greater sense of purpose, perhaps due to a different backstory or a unique encounter. For example, if he had a more tragic event in his past related to the supernatural, it could shape him into a more brooding and focused character.
Start with giving the OC Sitri a distinct personality trait. For example, if they are extremely curious, it can drive their actions and decisions. They could be constantly exploring the world of Highschool DxD and getting into all sorts of situations because of their curiosity.
Another theme could be adventure. They might go on quests together, facing various challenges that test their relationship and individual strengths. For example, they could be on a mission to save a kingdom or defeat a powerful enemy.
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.