One aspect could be the complex relationship between Sebastian and Ciel in the fanfic. Sebastian's jealousy might stem from his possessive nature over Ciel. He is Ciel's butler but also has a deeper, perhaps unspoken bond. This jealousy could add a new layer of tension to their interactions, for example, when other characters get too close to Ciel. It might lead to some interesting plot developments like Sebastian becoming more protective or overbearing in a way that both confounds and endears him to Ciel.
The 'sebastian x ciel modern fanfic' often explores different themes. For example, it could focus on how they adapt to modern society's values. Sebastian, with his old - world values, might clash with modern ideas, while Ciel has to navigate the fast - paced modern world. The fanfic might also play with the idea of their relationship being discovered in a more open - minded but still judgmental modern society.
One popular trope is the 'fish out of water' for Sebastian. As he is from a different era or world in a sense, seeing him adjust to modern technology like smartphones and the internet can be really interesting. For example, he might be confused by social media but quickly learn to use it to protect Ciel.
I really like 'The Crimson Contract'. It takes their relationship in a unique direction. It has a great plot that isn't just about the romantic aspect but also about the power dynamics between Sebastian and Ciel. It's full of interesting twists and turns.
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.
In these fanfics, a recurring theme is the power dynamic. With Sebastian being jealous, it can either strengthen or weaken the power he has over Ciel. If he becomes over - protective due to jealousy, Ciel might gain some power in the relationship as Sebastian's actions are more driven by emotion. Another theme is the idea of loyalty. Sebastian's jealousy could be seen as an extreme form of loyalty, not wanting anyone else to have what he considers his (in relation to Ciel). And of course, the theme of love, in a very complex and often unspoken way, is also quite common as the jealousy is often a sign of deeper feelings.
The theme of redemption is also common. Ciel's past traumas and his journey towards some form of redemption are intertwined with his relationship with Sebastian. In many fanfictions, Sebastian becomes a part of Ciel's path to either find peace or seek revenge in a more profound way than in the original story.
A good sebastian x ciel yaoi fanfic should have well - developed characters. Since we already know the basic personalities of Sebastian and Ciel from the original work, the fanfic should expand on them in a believable way. For example, showing how their relationship might change their individual growth.
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.
Yes, there are quite a few. You can start by looking on popular fanfiction websites like Archive of Our Own. Some works might explore unique storylines where a female Ciel has different interactions with Sebastian compared to the original male Ciel. However, the quality can vary greatly, so it's important to read reviews or summaries before diving in.