undertale and underfell

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.

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.

Sans is often a very popular character in these fanfictions. In both Undertale and Underfell, he has a distinct personality. In Underfell, his more edgy and somewhat darker side can create interesting interactions when combined with the regular Undertale Sans.

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.

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.

Frisk is also quite popular. Their role as the main character in Undertale and how they would interact with the darker or different versions of characters in Underfell and the swapped - up world of Underswap makes for great fanfiction material. They can be the mediator or the catalyst for change in the crossover story.

One interesting plotline could be the clash of different character personalities. For example, the more aggressive characters from Underfell interacting with the kinder ones from Undertale. They might start off not getting along but gradually learn from each other.

A plot could involve a love story between a character from Undertale and one from Underfell. Their different worlds' values and cultures clash, but they still manage to find common ground and fall in love. This could lead to them trying to bridge the gap between the two universes to be together.

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.

To write a great Undertale Underfell Sans x Fell Toriel fanfiction, you need to research the Underfell universe thoroughly. Know the rules, the power dynamics, and the overall atmosphere. When it comes to their relationship, start with small moments. Maybe Fell Sans brings Fell Toriel a small gift, like a flower from the dangerous parts of the Underground. This simple act can start to break the ice between them. As for the writing style, use vivid descriptions to bring the Underfell setting to life. Describe the dark corridors and the menacing monsters in the background as their relationship unfolds.