First, you need to be familiar with both the Sonic and Archie universes. Know their characters, settings, and storylines. Then, come up with an interesting concept for the crossover. It could be a simple adventure where the characters meet by chance, or a more complex plot involving a shared threat.
One possible plot could be that an ancient evil threatens both the Sonic X universe and the Sonic Boom universe simultaneously. Sonic from Sonic X and Sonic from Sonic Boom have to team up, along with their respective friends. They could start by accidentally crossing into each other's worlds through some sort of interdimensional rift. At first, they might be a bit confused and even a little competitive, but as they realize the scale of the threat, they combine their unique skills. Sonic X's Sonic is more used to high - tech environments and has different power - ups, while Sonic Boom's Sonic is more in tune with his natural island surroundings. Together, they could battle the evil and in the process, learn a lot from each other and their friends, ultimately saving both universes.
Eggman Nega could be a great main antagonist. He has the intelligence and the desire for power. He could find a way to open portals between the Sonic X and Sonic Boom universes to steal resources and technology from both. His plans would force Sonic X's Sonic and Sonic Boom's Sonic to team up against him. He could use his robotic creations from both universes, combining the advanced tech from Sonic X and the more rustic, yet effective, machines from Sonic Boom.
One common theme is adventure. Since Sonic and his siblings are known for their fast - paced adventures, when they cross over into other universes in fanfiction, it often leads to new and exciting adventures. For example, exploring new lands or facing new villains.
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.
A common theme is the clash of different powers. Sonic has his super speed and unique abilities, while the RWBY characters have their own semblances and combat skills. The fanfictions often explore how these powers interact when they meet. For example, how Sonic's speed can be used against the Grimm or in battles with RWBY villains.
One common theme is the clash of different powers. Sonic has his super speed and acrobatic abilities, while Naruto has his chakra - based ninja techniques. So in many crossovers, they have to find a way to combine their powers to defeat a common enemy.
Another theme is friendship. The idea of Sonic and the DBZ characters becoming friends and working together against common enemies is quite prevalent. For instance, Sonic might team up with Goku to save both their worlds from a powerful villain. This theme explores how different personalities from two distinct universes can bond over a common goal. It also shows the value of cooperation across different species and power levels.
One popular Sonic crossover fanfiction might be the one where Sonic crosses over with Mario. It often involves the two iconic characters teaming up to face a common threat in a world that combines elements from both their universes. Another could be Sonic and Naruto's crossover, where Sonic's speed and Naruto's ninja skills create interesting storylines.
Another unique aspect is the character interactions. Sonic is a heroic figure in his own right, and the KND kids are also heroes in their own world. When they meet, there are clashes in their ways of doing things at first. But as the story progresses, they learn from each other. The KND might learn about Sonic's more straightforward approach to fighting evil, and Sonic could learn about the KND's clever use of teamwork and planning.