Love in the face of adversity is likely to be a common theme. Maybe there are external forces, like enemies or difficult circumstances, that try to keep them apart. But they fight against these odds to stay together. Another theme could be the discovery of each other's true selves. As they fall in love, they might learn more about each other's hidden strengths, weaknesses, and personalities.
One common theme could be the struggle of their relationship in a complex fictional world.
Often, themes like loyalty and sacrifice might be present. Since they are in a relationship in the fanfiction, they may have to be loyal to each other in the face of various challenges. And sacrifice for the sake of the other's well - being could also be a part of it. For example, one might sacrifice their own goals to help the other achieve something.
Friendship is a common theme. Since they are paired in the fanfic, their relationship often develops into a strong bond of friendship as they go through various situations together.
One common theme is the journey of self - discovery. As they fall in love, both Ragna and Makoto often learn more about themselves. For example, they might discover new aspects of their personalities or values through their relationship.
One common theme is the exploration of her character in a different gender context. Writers might play with how she interacts with other characters differently as a female. For example, her relationships with male characters could take on new dynamics.
One common theme is the exploration of their different personalities coming together. Rachel is often depicted as mysterious and powerful, while Ragna is more hot - headed. Their relationship dynamic is a big draw.
Protection is also a common theme. Ragna is often portrayed as the protector of Noel. He will go to great lengths to keep her safe from the various threats in the fanfic world. This theme of protection shows the depth of his feelings for her and also creates a lot of tension and drama in the stories.
A common theme is the exploration of Ragna's character from different perspectives. In a harem fanfic setting, different characters in the harem bring out different sides of Ragna. There could also be themes of friendship evolving into something more. And sometimes, there are elements of adventure where Ragna and his harem are involved in some sort of mission or journey together, which further deepens their relationships.
One common theme is the clash of their different backgrounds. Ragna comes from his own world with its own set of rules and Blake from hers. Their interaction often involves dealing with these differences.
I'm not sure about specific 'ragna and nine love fanfiction' stories. You could try searching on fanfiction platforms like Archive of Our Own or FanFiction.net.
Love and sacrifice are common themes. Since their relationship is complex, often fanfics explore how they would sacrifice for each other. For example, Ragna might put himself in danger to protect Noel.
One common theme is the development of their friendship into something more. Since they start as colleagues and friends, many fanfictions explore how that relationship deepens romantically over time.