One common theme is mystery. Since both characters have elements of mystery in their original lore, fanfictions often explore that further. Another theme is power dynamics. Given their different abilities, how they interact in terms of power is often explored. And friendship or a deeper connection is also a common theme as writers like to explore the relationship between these two unique characters.
One common theme is mystery. Since both Gaster and Sans have mysterious backstories in the original game, fanfictions often explore and expand on these mysteries, especially in relation to their relationship.
A sense of otherworldliness is common too. Since Gaster Sans is from a rather strange and unique universe, the fanfictions often play with the idea of the reader being in a very different, almost alien world. This can lead to themes of adjustment, as the reader tries to fit into this new world while being in a relationship with Gaster Sans.
Well, I'm not sure about all of them, but 'A Glimpse Beyond' is a sans x gaster fanfiction that's quite good. It shows their relationship in a more mysterious light, with a lot of plot twists. And then there's 'Fractured Souls' where they deal with some sort of crisis together, and it really shows the depth of their bond. Oh, and 'Whispers of the Ancients' is also worth checking out as it gives a different perspective on their characters and how they fit together in the story.
One popular 'gaster x sans fanfiction' is 'The Lost Experiments'. It delves into the mysterious relationship between Gaster and Sans, exploring their shared past in the Underground. The story is full of intrigue as it uncovers secrets that were long buried.
Well, 'The Encounter with Gaster Sans' is also a popular one. It starts with an unexpected encounter between the reader and Gaster Sans, and then slowly builds up the relationship. There are a lot of emotional moments and the author does a great job of describing the world they exist in.
At first, Sans would probably be a bit shocked, but then he'd turn on his laid - back, sarcastic attitude. He might make jokes at Gaster's expense, which could either annoy Gaster or make him respect Sans more. If Gaster tries to harm him, Sans could use his shortcuts to dodge attacks and try to find a way to reverse the situation. He'd also likely be thinking about how this affects his friends in the Underground, especially Papyrus, and try to find a way back to them.
One possible reason could be for some sort of experiment. Gaster is often depicted as a mysterious scientist in the Undertale lore, and Sans has unique abilities. Maybe Gaster wants to study Sans' power over time and space. Another reason could be related to secrets. Sans might know something about Gaster's past or the true nature of the Underground that Gaster wants to keep hidden, so he kidnaps Sans to prevent him from revealing it.
Well, it could be about Gaster suddenly reappearing in the lives of Sans and Papyrus. Maybe he has some important knowledge or a mission for them. For example, he might need their help to fix something in the Underground that's going wrong.
Obviously, Sans and Papyrus are the two main characters who we already know well from the original Undertale. They have distinct personalities that will play a big role in how they interact with Gaster. Gaster, on the other hand, is the enigma. His presence will likely drive the story as Sans and Papyrus try to figure out who he is now and what he wants, so he's also a main character in this fanfiction.