One interesting idea could be a fanfic that focuses on the backstories of the minor characters in Deltarune. For example, exploring what the lives of the Darkners were like before the events of the game.
A time - travel themed deltarune fanfic would be cool. Maybe the main characters go back in time to change a crucial event in the Deltarune world, which then has a huge impact on the current story and relationships.
Another plot idea is a story where the antagonists from both games, such as Flowey from Undertale and the King from Deltarune, form an alliance. Their goal could be to take over both universes. This would force the heroes of both games to work together. The fanfic could explore how the different characters with their own powers and personalities interact and strategize to defeat this powerful alliance.
One idea could be a Deltarune and Undertale crossover. You could have the characters from Deltarune end up in the Underground from Undertale. They might interact with Sans and Papyrus, for example. The contrast between the two worlds' rules and the different character personalities would create a lot of interesting scenarios.
One idea could be that Danny Phantom gets sucked into the Deltarune world. He could use his ghost powers to help the characters in their quests. Maybe he teams up with Kris to fight against the dark forces in the Dark World.
One idea could be that the characters from Undertale find themselves in the world of Deltarune. For example, Frisk could end up in the Dark World and have to figure out how to get back home while interacting with the Deltarune characters. They might team up with Kris to fight against new threats that are a combination of both universes' villains.
One idea could be that the characters from Undertale find themselves in the Deltarune world and have to adapt to its different rules and characters. For example, Sans could meet Ralsei and they could have a humorous exchange about the nature of their respective universes.
Maybe in the fanfiction, the Dark Fountains from Deltarune start appearing in the Undertale world. This causes chaos as the monsters in Undertale don't understand what these strange fountains are. Frisk, along with the Deltarune trio, has to figure out how to stop the fountains from spreading darkness. They could learn from each other's powers and strategies. For example, Frisk could teach Kris about determination in a more in - depth way, and Kris could show Frisk how to navigate the strange new areas created by the Dark Fountains.
One interesting concept could be the crossover of characters' personalities. For example, how the determination trait from Undertale might interact with the more mysterious elements in Deltarune. Another could be the exploration of different timelines. Since both games have some elements related to time and alternate realities, a fanfic might delve into how these timelines could cross or affect each other. Also, the unique magic systems of both could be combined in creative ways, like how the soul powers in Undertale might work with the magic in Deltarune.
One interesting 'Deltarune' fanfiction could be the ones that explore the backstories of the characters more in - depth. For example, there might be fanfictions focusing on Kris's inner thoughts and struggles. Another type could be those that create alternate universes where the game's events take a different turn, like if the Darkners and Lightners had a more peaceful co - existence from the start.
The fact that it's based on Deltarune. Deltarune has such a rich and mysterious world, and the 'chara play' aspect allows fans to really get into the heads of the characters. It gives a new perspective on the story and the relationships within it.
A good 'Kris x Susie Deltarune fanfic' often plays with the unique setting of Deltarune. It might introduce new elements to the world that affect Kris and Susie's relationship. Also, the way the author develops their characters beyond what we see in the game, like giving them new hobbies or backstories, can be really captivating. The fanfic could also explore different timelines or alternate universes where their relationship takes on new forms. This allows for a lot of creativity and keeps the readers engaged.