She would probably have a complex relationship with the Arthurian characters. For example, with Artoria, there would be a lot of tension. Artoria might see her as a reminder of Mordred's betrayal. But the OC could also try to show Artoria that she is her own person. With other Servants like Archer, she might be initially seen as an enemy, but if she shows her good intentions, they could become allies.
Well, it could be about her trying to redeem the name of her father. Maybe she joins the Holy Grail War not for power but to prove that Mordred's line can be heroic. She might form alliances with some of the traditional heroes, like Saber, and they initially have a lot of mistrust but over time come to respect each other.
Love and friendship are also common themes. An OC could develop a deep friendship or even fall in love with Mordred. This relationship can be complicated by Mordred's status as a Servant and the events of the Holy Grail War. It can also be a source of character development for both the OC and Mordred. For instance, Mordred might learn about different forms of love and loyalty through her relationship with the OC, while the OC might grow in courage and determination as they get closer to Mordred.
There are often fanfiction communities on Reddit as well. The r/fatestaynight subreddit might have some threads dedicated to OC and Mordred fanfiction. People often share their own works or recommend ones they've read. You can also look for Tumblr blogs that are focused on Fate Stay Night. Some bloggers are really into fanfiction and might have reblogged or written some interesting stories about OCs and Mordred.
One common theme is the struggle for identity. Mordred already has her own issues regarding her identity in the Fate series, and when an oc is introduced, it often adds another layer to this exploration. For example, an oc might be from a different background that challenges Mordred's views on herself and her place in the world.
She might initially be feared by the Winchester brothers. But as they learn more about her, they could form an uneasy alliance. For example, if she shows that she wants to resist her father's evil ways.
Saber, with her noble and chivalrous nature, might initially clash with the more laid - back and modern - thinking demigods from Percy Jackson. But she could also earn their respect with her combat skills. Archer, on the other hand, might be intrigued by the Greek magic and try to analyze it. He could teach some of the demigods about his own brand of magecraft in return.
The role could be that of an outcast. People might shun her because of her father, and she has to find a way to survive on her own. This could lead to her becoming a rogue figure, making her own rules in a world that has no place for her.
In an 'daughter of Mordred' OC fanfiction, she could be a complex character. Maybe she struggles with the dark legacy of her father. She might be on a journey to redeem the family name or she could be lured towards the same dark path Mordred once walked. For example, she could be in a world where the Arthurian legends are still very much alive in the background, and her actions are constantly judged in the light of her father's deeds.
One common theme is self - discovery. Both Mordred and the OC often go through a journey of understanding themselves better because of their relationship. Another theme is loyalty. They usually show great loyalty to each other in the face of various difficulties.
Naruto's chakra - based powers and Fem Gilgamesh's magic would be an interesting combination. Naruto could use his Rasengan, a powerful chakra - based attack, while Fem Gilgamesh could enhance it with her magic, making it even more destructive. Or she could use her magic to create barriers to protect Naruto while he charges up for a big attack.