One great Dream Sans x Nightmare Sans fanfiction is 'The Dual Existence'. It beautifully explores the complex relationship between them. The story dives deep into their opposing natures yet shows how they are also two sides of the same coin. It has some really well - written dialogue that gives a great insight into their characters.
The plot also matters. It could be about their rivalry, or a journey towards understanding each other. For instance, a plot where they are forced to team up against a common enemy can be really engaging. This not only shows their individual strengths and weaknesses but also how they can complement each other in a way.
One common theme is friendship. Since they are from different 'worlds' in the Undertale AU, their journey to become friends is often explored. Another theme is redemption. Sometimes Cross Sans might have a troubled past and Dream Sans helps him find a new path.
One common theme is the struggle between good and evil, as Dream Sans is often associated with positive aspects and Nightmare Sans with negative ones. Their relationship in fanfics can explore how they deal with their opposing natures.
One popular cross sans x dream sans fanfiction is 'The Meeting of Two Souls'. It beautifully depicts their first encounter and the development of their unique relationship. Another great one is 'Cross and Dream's Adventure' which takes them on an exciting journey through different AU's.
Some Tumblr blogs are dedicated to sharing Undertale fanfics as well. You can search for tags like '#dream sans x nightmare sans fanfic' on Tumblr. These blogs often have a community of fans who are into the same kind of content. They might also provide reviews or recommendations for other great fanfics in this category.
I'm not entirely sure as it could be a very specific fanfiction concept. It might involve a scenario where the reader character in an Undertale fanfiction related to Dream Sans meets an unfortunate end for some reason within the fictional world created by the fanfic's author.
It could also be an internal identifier used by a company or a group. Maybe it's related to a game or a fictional universe that is not associated with adult themes. For instance, it could be a level or an area in a science - fiction based game.
Another good one is '999: Nine Hours, Nine Persons, Nine Doors'. It has a really interesting and mysterious plot. You are trapped on a ship with eight other people and have to solve puzzles and make choices that will determine your fate and the fate of others. The story twists and turns and keeps you on the edge of your seat.
For beginners, 'Phoenix Wright: Ace Attorney' is a great start. It has a simple enough gameplay mechanic where you just need to present evidence at the right time. The story is easy to follow and the characters are really charming. You get to be a defense attorney and solve some really interesting cases.