The Underswap Sans Dark Story can be really complex. It typically shows a deviation from the positive and light - hearted aspects associated with the normal Underswap Sans. His relationships with other characters like Papyrus are likely to be different. Papyrus might not be able to reach this darker Sans in the same way as he could in the original story. Also, the overall atmosphere in the Underground in this dark story would be more foreboding. The dark - story Sans might have a different set of rules or values that he adheres to, which are not in line with the more friendly and helpful nature of the original Underswap Sans.
The main characters include the altered Underswap Sans. He's the central figure around which the dark story revolves. Papyrus also plays a crucial role as his brother. Their dynamic would be different from the normal Underswap scenario. And any other significant monsters in the Underground that interact with the dark Sans, like Alphys or Undyne, could also be considered main characters as their reactions to this new, darker Sans would shape the story.
One great idea for a fanfiction could be a story where Underswap Sans and Underswap Papyrus go on an adventure in the Underground. Maybe they encounter a strange new monster that no one has ever seen before. They have to use their unique abilities to figure out how to deal with this new threat.
Common themes include loyalty. They are extremely loyal to each other in most fanfics. Another one is the theme of overcoming challenges. Whether it's dealing with other characters or facing difficulties in their world, they work together to overcome them. There's also the theme of fun and humor. Their interactions are often filled with jokes and light - hearted moments, which makes the fanfics enjoyable to read.
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.
The popularity might be due to the fact that it allows for a lot of exploration of the Undertale lore. Error Sans is often associated with glitching and breaking things in the game's world, while UnderSwap Sans comes from a swapped - personality version of the original. A fanfic can play around with how these two different concepts interact. Maybe it shows how Error Sans reacts to the more positive and light - hearted UnderSwap Sans, or vice versa. It gives fans a chance to see different sides of these characters that they might not get to see in the original game.
To write a great Error Sans x UnderSwap Sans fanfic, start with a strong concept. Maybe it's a story about how UnderSwap Sans tries to 'fix' Error Sans in some way. Research the existing fan works and the official Undertale lore to get inspiration. When it comes to the writing itself, build up the relationship between the two characters gradually. Show how they initially react to each other, and then how their relationship evolves over time. Use vivid descriptions for their actions and the settings around them. For example, describe how Error Sans' glitches affect the environment they are in, and how UnderSwap Sans' positive energy can sometimes counteract that. Also, make sure the pacing of the story is right, not too slow or too fast.
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.
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.