The 'slow - burn romance' is quite prevalent. Writers like to build the relationship between Sebastian and the female oc gradually, showing their growing attraction and connection over time. There's also the 'mysterious origin' trope for the female oc. She might have a hidden past or special powers that draw Sebastian to her, and this mystery unfolds throughout the story, adding depth and intrigue to the relationship.
A common trope is the 'forbidden love' trope. Since Sebastian has his own duties and often a dark nature in many interpretations, a relationship with a female oc can be seen as something that goes against the norm or is dangerous. Another is the 'damsel in distress' trope where the female oc gets into trouble and Sebastian has to save her.
One common trope is the 'fish out of water' situation. For example, if the OC is from a different time or place than the canon world, like an OC from modern times ending up in Middle - earth in a Lord of the Rings 'oc x cannon fanfiction'. Another is the 'love at first sight' trope, where the OC and the canon character fall for each other immediately. It's often used to quickly establish a relationship in the story.
One often - seen trope is the 'oc with a special power'. This power can either be a threat or an asset to the Akatsuki. It creates interesting dynamics as the Akatsuki members might want to use the oc for their power or protect them from others who would. Also, there's the 'redemption arc' trope for the Akatsuki through the oc's influence. The oc might make one or more of the members question their actions and seek a different path.
One common trope is the over - protective yandere. The yandere character in these fanfics often goes to extreme lengths to protect the Marvel OC, even if it means going against other characters or the law. For example, they might fight off villains in a very brutal way just to keep the OC safe.
One common trope is the 'opposites attract' scenario. The grand highblood's often menacing or complex nature is contrasted with the oc's more innocent or different qualities. This creates a dynamic relationship.
One popular trope is the 'Forbidden Love' aspect. Since Sebastian is a demon and Ciel is a human, their relationship can be seen as something that goes against the natural order. Another is the 'Power Struggle' trope. Ciel may try to assert his authority over Sebastian, but Sebastian's demonic nature gives him an edge in certain situations. 'Soul Bond' is also common. Given their contract and the connection it implies, fanfictions often explore the deeper spiritual and emotional bond that might develop between them.
One common theme is the exploration of a romantic relationship between Sebastian and the OC. Writers often create scenarios where the two characters are drawn to each other in unexpected ways.
One common theme is the power dynamic. Since Sebastian is often a powerful character, the relationship with the OC can explore how power is balanced or unbalanced between them. For example, in some stories, the OC might be initially powerless against Sebastian but then find ways to assert themselves.
Another theme is romance. Some fanfictions explore a romantic relationship between Female Claude and Sebastian. This can involve a slow - burn build - up of feelings, secret meetings, and the struggle to come to terms with their feelings in the context of their complex world.
One common theme is the exploration of a different kind of relationship dynamic. Since Ciel is female, there can be more of an emphasis on romantic or platonic love. Another theme could be the role - reversal in some aspects. For example, how a female Ciel might handle certain situations differently from the male version. Also, the theme of self - discovery for Ciel as a female in a world dominated by men can be present.
One popular trope is the 'love - hate' relationship. Grell is head - over - heels for Sebastian, but Sebastian is mostly indifferent or even annoyed. Another is the 'rivalry' trope, as they are both strong in their own ways. Grell with his unique scythe skills and Sebastian with his demonic powers.