What Makes a Good Underswap Sans x Reader Fanfiction?

One great Underswap Sans x Reader fanfiction is 'A Swap in Fate'. It has a really engaging plot where the reader character is transported to the Underswap universe and forms a unique bond with Sans. The author does a wonderful job of portraying Sans' personality in this AU.

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.

The plot matters a great deal. It could be about their adventures in the Underswap world, or it could be a more emotional story about how they deal with the changes in their relationship due to the swap. A good plot keeps the reader engaged, whether it's full of action, humor, or heart - felt moments. For instance, a plot where they have to work together to save their swapped world from a threat would be exciting.

Characterization is key. A good fanfic should accurately portray the personalities of both Underswap Sans and Underfell Sans. Their unique traits, like Underswap Sans' more positive and friendly nature compared to Underfell Sans' tougher exterior, should be well - presented.

The writing style is crucial. A good fanfic will have smooth and engaging prose. It won't be full of grammar and spelling mistakes. For this pairing specifically, the interactions between the two should be believable. They come from different 'universes' within the Undertale multiverse, so how they react to each other's differences and similarities can make or break the story. Also, a bit of humor or emotional depth can really enhance the fanfic.

You can start by looking on Archive of Our Own (AO3). It has a large collection of fanfictions for various fandoms, including the Undertale AU crossovers like Underswap Sans x Underfell Sans. Another place could be Fanfiction.net, though the quality may vary more there. Additionally, Tumblr sometimes has users sharing or recommending such fanfictions in the Undertale fandom tags.

A plotline could be that they discover a hidden part of the Underground. This new area could have different rules and strange creatures. They have to adapt quickly to survive and also figure out how this new place relates to the rest of the Underground.

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.

There's a really cool fanfic called 'FellSwap Encounters'. It delves deep into the relationship between underfell sans and underswap sans. It starts with a chance meeting and then shows how they gradually understand and support each other. The author does a great job of showing their different characteristics and how they complement one another.

Character development is key. Sans has a distinct personality in the game, and a good fanfic will expand on that while also creating a well - rounded reader character. Also, an interesting plot that brings them together in a unique way, like a mystery they have to solve together or a shared goal.