One possible main antagonist could be an ancient evil that has been awakened by the discovery of the Dark Excalibur. This entity might be seeking to use Sonic as a pawn to spread chaos and destruction. For example, it could be a long - forgotten dark wizard who once forged the Excalibur for evil purposes.
There could be new original antagonists created specifically for the fanfiction. These might be dark entities that are related to the source of Dark Sonic's power, trying to either control him or use his power to spread chaos in Sonic's world.
One interesting concept could be a new power - up for Sonic. In Dark Excalibur Sonic fanfiction, perhaps Sonic discovers a dark - themed power that is related to the Excalibur. This power could change his appearance and abilities, making him look more like a 'dark hero'.
One possible main antagonist could be Dr. Robotnik's sister, who is even more devious and has a different set of robotic creations. She could be jealous of Sonic's speed and popularity and wants to take over the world just like her brother, but with her own style.
Well, Sonic is the central figure. But other characters like Amy Rose could be important. She might be heartbroken to see Sonic turn dark and try to use her love for him to bring him back. There could also be some new characters created specifically for this fanfiction. For example, a mysterious character who has the power to either make Sonic darker or has the key to bringing him back to normal.
There could also be some new characters introduced in this fanfiction. Maybe a mysterious figure who has the power to control Dark Sonic or someone who has a connection to the origin of Dark Sonic. These new characters can bring fresh plot twists and new relationships to the story.
The main antagonists might be a new breed of ninja created by some dark jutsu or experiment within the 'dark empire' fanfiction. These new ninjas could have powers that are a threat to Naruto and his friends, and they are bent on spreading chaos and darkness throughout the Naruto world. They might have no moral compass and be solely focused on domination.
The Hidden Leaf Village elders could be antagonists. If Naruto turns dark, they might see him as a threat to their power and try to stop him. Their actions against Naruto could further fuel his descent into darkness.
Well, obviously Dark Gaia itself could be the main antagonist. It has the power to cause chaos and destruction, and Sonic would have to stop it from wreaking havoc on the world.
The main characters are, of course, Dark Sonic and Shadow. Dark Sonic is a more menacing and chaotic version of Sonic. He has a darker personality and often acts on more primal instincts. Shadow, on the other hand, is a complex character with a tragic past. He is a powerful hedgehog created by humans. In the fanfiction, they are the central focus, with their interactions driving the story forward.
Sonic is most likely the main character. Since it's a Sonic fanfiction, he would be the one to take on the Dark Gaia monster. His friends like Tails or Knuckles could also be in it. Tails might be there to provide technical support, while Knuckles could help in combat or with knowledge about the Dark Gaia entity.