Maybe it's because some writers want to add more drama and conflict, but it's not a good trend.
I think it could be that people try to take these universes in darker directions for shock value. But it often goes too far and can be uncomfortable for readers. Also, maybe some don't understand the original concepts well and go off-track.
It could be that a few writers have a distorted view of these fanfiction universes and think abuse makes the story more 'interesting'. However, this kind of approach is actually harmful and doesn't do justice to the potential of the source material.
The theme of redemption can also be found. Sometimes, the more negative characters from underfell might find a chance at redemption through their interactions with the positive characters in underswap. It's like they get a new perspective on life and start to change for the better.
Well, 'underfell' is often a darker or more 'fell' (evil or negative) take on a particular fictional universe. Fanfiction related to it might involve stories where characters face abuse in that darker setting. However, it's important to note that abuse in fanfiction can cover a wide range of things like emotional, physical or psychological abuse of the characters within the framework of that underfell world.
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.
One common theme is the exploration of differences. Underfell sans and underswap papyrus are from different universes with distinct personalities. Fanfictions often focus on how they deal with these differences, like underfell sans's more aggressive nature compared to underswap papyrus's more positive and energetic self.
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.
Another theme is friendship or partnership. They often come together to face challenges in the Underground. For example, in many fanfictions, they join forces to defeat a powerful monster or solve a mystery that threatens their world. This theme of unity despite their differences is really appealing.
One possible plot twist could be that Underfell Sans turns out to be a long - lost relative of one of the Underswap characters. Another could be that a villain from Underfell follows him to the Underswap world and causes chaos. Or perhaps Underfell Sans is actually there to steal something important from the Underswap world but has a change of heart halfway through.
The contrast between the two characters. Underswap Sans is more laid - back and friendly compared to Underfell Sans who is more rough and edgy. When they interact in fanfictions, it creates a lot of interesting dynamics, like how they might clash or gradually understand each other.
One popular underfell x underswap fanfiction is 'A Tale of Two Universes'. It beautifully weaves the dark and edgy elements of underfell with the more light - hearted and swapped personalities of underswap. The story focuses on how characters from both universes interact and face challenges together.