In such a fanfiction, there could be a lot of conflict. Underfell Sans is from a more hostile AU than Undertale. He might initially be distrustful when meeting the characters from Undertale. For example, he could misunderstand their kindness as weakness or a trick.
Well, perhaps there would be a journey of self - discovery for Underfell Sans. Meeting the more innocent characters of Undertale could make him question his own world's values. He might start to see that there are other ways to live and interact, not just through aggression and power plays.
One possibility is that they team up to face a common threat. Maybe some kind of dark force that could endanger both the Underfell and Undertale universes. During this process, they learn from each other's strengths. The Undertale characters could teach Underfell Sans about compassion, while he could show them how to be more assertive in a dangerous situation.
Well, in a 'underfell sans meets underswap fanfiction', it might involve a clash of cultures, so to speak. Underfell Sans is from a darker, more dangerous world where survival is tough. When he meets the Underswap characters, who are often more laid - back and kind - hearted, it could lead to some really cool storylines. For example, he could learn about friendship in a new way from the Underswap Sans, or get into trouble while trying to adapt to their more peaceful world.
Frisk would be a likely candidate. Since Frisk is the main character in Undertale and has a very adaptable personality. They could approach Underfell Sans with an open mind and try to understand him.
Another scenario could be that there's immediate conflict. Sans might suspect that this different - looking Chara has some malicious intent towards his world or his friends. So he could start a fight right away. But as the encounter progresses, they might start to understand each other better and the fight could turn into a more of a philosophical debate about the nature of their respective worlds and the actions they've taken in the past.
The fan base loves these characters so much that seeing them interact in new and unexpected ways is always a treat. The relationship between them can be explored in so many different ways, from friendship to rivalry. And the unique art styles and interpretations that often come with these fanfictions add to the overall appeal. There are also some really emotional stories that can be told about them finding common ground or learning from each other, which really tugs at the heartstrings of the readers.
One idea could be a story where Fell Sans and Fell Toriel form an unlikely alliance. Maybe they start by just having chance encounters in the Underground, and over time, they realize they share a common goal, like trying to bring some sense of order to the chaotic Underfell world. This could involve them working together to deal with unruly monsters and gradually growing to respect each other.
There's 'Sans - Bound'. This fanfiction focuses on the challenges they face when they are forced to work together. It's not just about their relationship but also about the world - building in the undertale and underfell universes. The descriptions of the settings are vivid and add to the overall charm of the story.
The appeal lies in the fact that these two characters represent different aspects of the same basic concept. Fans are drawn to seeing how they can coexist or clash. Additionally, the fanfiction community around them has created a whole range of stories that range from heart - warming to action - packed, which gives readers a lot of variety to choose from.
There's also 'Sibling Rivalry Reimagined' which delves deep into how their personalities from their respective universes interact. It has some really interesting character development for both Sanses. It shows how their differences can lead to both conflict and unexpected understanding. The author does a great job of portraying their emotions and the way they communicate, which is quite different from the original game's interactions.
Well, it could be a really intense encounter. Maybe there would be a battle of wits as they try to figure out each other's motives. Since Horrortale Sans has been through a lot in his own universe, he might be more cautious around the other Sans. And the other Sans could be either curious or a bit scared of Horrortale Sans's appearance and the aura of horror that surrounds him.
Well, Naruto might be really confused by Sans' laid - back attitude. Maybe Naruto would try to show off his ninja skills, and Sans would just be there, nonchalantly making his puns. It could be a really interesting clash of two very different universes.