Well, in a 'Sonic gets kidnapped by Eggman' fanfiction, there could be a plot where Eggman tries to turn Sonic into a weapon. He might experiment on Sonic, but Sonic resists with his strong will. Meanwhile, Sonic's friends like Tails start searching for him. Tails could use his intelligence to track down Eggman's hideout. And when they finally find Sonic, there's an epic battle between Sonic's friends and Eggman's forces to free Sonic.
Obviously, Sonic and Eggman are the key characters. Sonic is the kidnapped one and Eggman is the kidnapper. But also, Tails could be a very important character. Since he is Sonic's best friend, he would likely be the first to try and rescue Sonic. Knuckles might also be involved. He could help in the search or be the muscle during the rescue mission.
One possibility is Dr. Eggman. He has always been after Sonic and wants to stop him. Kidnapping Sonic would be a way for him to achieve his evil goals.
Tails would be the first one to come to Sonic's aid. His intelligence and flying ability would be very useful in finding Sonic and getting past Eggman's defenses.
Well, Sonic might be held in a high - tech prison. His friends like Tails would start a rescue mission. They could use their unique skills, Tails with his flying and mechanical abilities, to track Sonic down.
A common theme is the battle between good and evil, with Sonic representing good and Eggman representing evil. They constantly fight over things like power, territory, or the Chaos Emeralds.
Well, obviously Sonic and Eggman are the main characters. Sonic is the speedy blue hero, always ready to save the day. Eggman, on the other hand, is the brilliant but often - misguided inventor. In fanfiction, their relationship can be re - imagined in many ways.
A really cool Sonic and Eggman fanfiction could be set in an alternate universe. In this universe, Sonic is not the hero he is in the main canon. Instead, he's more of an anti - hero, and Eggman is the one trying to save the world from Sonic's reckless behavior. It flips the traditional roles and makes for a very engaging read.
In this kind of fanfiction, Sonic might be locked in one of Eggman's elaborate traps. Eggman could be planning to use Sonic's speed for his own evil experiments or to finally defeat him once and for all. Sonic would surely try to escape using his wits and speed.
One interesting plot could be Sonic and Eggman having to team up against a new, more powerful enemy that threatens their world. They put aside their differences and combine their unique skills, like Sonic's speed and Eggman's inventions, to defeat the foe.