Obviously, Gaster himself is likely to be a main character. His mysterious nature makes him a central focus as readers are eager to learn more about him. Another potential main character could be Frisk. Their ability to reset and influence the game's world could be very interesting when combined with Gaster's enigma. They could either be allies or have some sort of conflict due to their different understandings of the world.
The concept of power dynamics is also fascinating. In a 'Undertale Gaster Crossover Fanfiction', Gaster's power, which is not fully understood in the original game, could be compared or combined with the powers of other characters. This might result in epic battles or the need for characters to cooperate in ways they never had to before in their respective stories.
There are fanfictions where Gaster is reunited with the other characters in unexpected ways. For example, a story could have him reappear during a crucial moment in the Underground's history and use his knowledge to change the fate of everyone. It could be really exciting as it might bring new plot twists and character developments.
The war between Gaster and Grillby in the fanfiction might have been sparked by a personal grudge or a competition for influence. Maybe there was a hidden secret that drove them apart and into conflict.
You can start by looking on popular fanfiction websites such as Archive of Our Own. Just search for 'Undertale Gaster' and you'll get a list of related fanfictions. Sort them by popularity or rating to find the ones that are well - liked.
You can try some popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of Undertale fanfictions, and you might be able to find Gaster x Asgore yaoi ones by using the search function.
There might be a fanfiction where Gaster, with his mysterious past and knowledge, helps Asgore deal with the guilt of past actions. As they spend time together, they discover new sides of each other and a yaoi - themed relationship blossoms. It could involve Gaster showing Asgore different perspectives on leadership and forgiveness.
One idea could be a crossover with the Harry Potter universe. Gaster could be a mysterious wizard from a far - off land who arrives at Hogwarts with his unique brand of magic that is based on his scientific experiments in his original world. Another could be a crossover with the Star Wars galaxy, where Gaster is a brilliant scientist working on some top - secret project for the Galactic Republic. Maybe he discovers a new form of energy that has implications for both the Force and the technology in the Star Wars universe.
Begin by brainstorming ideas for the crossover. For a Gaster Crossover Fanfiction, say with the Doctor Who universe, think about how Gaster and the Doctor would interact. They are both very intelligent characters, but with different ways of approaching problems. You could start with a scene that sets the stage for the crossover, like Gaster detecting some strange time - space anomalies that lead him to cross paths with the Doctor. Then, develop your characters further. What would Gaster think of the TARDIS? How would the Doctor react to Gaster's strange experiments? Build your story from these initial ideas, adding conflict and resolution as you go along.
Well, a unique feature is the combination of different art styles. Sonic has a very distinct, bright and energetic art style, while Undertale has a more pixelated, RPG - ish look. In the crossover fanfiction, writers often find creative ways to merge these visual elements into their descriptions. For example, they might describe Sonic running through the Underground's pixelated landscapes.