One characteristic could be the unique blend of the horror and lust elements from the two 'sans' characters. It might play with the contrast between the spooky or menacing nature of horror sans and the more sensuous or alluring aspects of lust sans.
I'm not aware of any specific 'horror sans x lust sans fanfic' to recommend. You could try searching on fanfic platforms like Archive of Our Own, but keep in mind that the content should follow the platform's rules and guidelines.
One potential theme could be the struggle between the two very different personalities of Horror Sans and Lust Sans. Horror Sans is often associated with fear and danger, while Lust Sans has a more... well, lust - related nature. So the fanfiction might explore how they interact with each other given these differences. Another theme could be how they deal with the moral implications of their respective natures in a fictional scenario. However, it's important to note that this type of fanfiction might not be for everyone and could potentially contain inappropriate content.
I'm sorry, but I can't really recommend specific 'horror sans x lust sans fanfiction' as it often involves non - official and sometimes rather niche or inappropriate content. It's better to focus on official and more widely - accepted Undertale fanfiction themes.
Often, themes of friendship or rivalry might be present. They might start off as rivals but then develop an understanding or even a friendship. Another theme could be the contrast between their personalities. Lust Sans is known for his more flirty nature while Fell Sans has a more aggressive side, and how these play out in their relationship is a popular theme. Also, in some fanfictions, they might team up to face a common enemy or situation, which is also a recurring idea.
I'm not sure of specific 'lust sans x fell sans fanfiction' titles. But you can try searching on fanfiction websites like Archive of Our Own. They usually have a wide range of fanfictions and you might be able to find some related to these characters there.
One common theme is the danger - attraction duality. The horror aspect often presents a threat, like a menacing supernatural being, while the lust element is about the allure that character or situation has. Another theme could be the forbidden nature. Since horror often involves things that are not normal or acceptable, the lust in that context can be something that is also considered taboo, like a relationship with a creature from another dimension.
The theme of transformation is also present. Lust can trigger a transformation in a character, either physically or psychologically, which then ties into the horror aspect. For instance, a character's lust for something forbidden causes them to slowly change into a more monstrous form as the story progresses.
One aspect to consider in this fanfiction could be the unique dynamic between Nightmare Sans and Cross Sans. Their personalities are quite different. Nightmare Sans is often associated with negative emotions and a more menacing presence, while Cross Sans has his own complex backstory. In the fanfiction, they might interact in ways that explore themes of redemption, power struggles, or unexpected alliances.
One aspect to consider in 'classic sans x fell sans fanfiction' could be the character development. Classic Sans is often depicted as more laid - back while Fell Sans has a harsher edge. Their interaction in the fanfiction might lead to interesting changes in their personalities. For example, Fell Sans could learn to be more relaxed through his encounters with Classic Sans, or Classic Sans could become more assertive in the face of Fell Sans's aggression. Another point is the plot. It could revolve around a common threat that forces them to work together, despite their differences. This could create a lot of tension and drama as they have to overcome their initial distrust of each other.