An experimental subject, a Force - sensitive being who manages to break free from the Empire's control and then becomes a key figure in fighting against the Empire's evil plans.
One main character could be a droid technician working for the Empire. They might be involved in creating new and more powerful droids for the Imperial military. A Twi'lek slave who has been forced to serve in an Imperial household could also be a main character. This character could be plotting their escape while also learning secrets about the Empire's inner workings. Additionally, a Mandalorian who has made a deal with the Empire to gain certain resources or advantages. But as time passes, they realize the true cost of serving the Empire.
A character could be a Force - sensitive child from the United Earth Empire. He was born with this power but was hidden away on Earth. When the Empire discovers his abilities, they want to use him as a weapon. However, he is befriended by a group of rebels who help him understand the true nature of the Force and fight against the Empire's evil plans.
One possible main character could be an Earth scientist. They would be in a unique position to study the Empire's technology and try to find a way to defend Earth.
It could be a former Imperial officer who has seen the error of his ways. After the fall of the Empire, he tries to live a normal life but is drawn back into the conflict when he discovers signs of the Empire's return. He uses his knowledge of Imperial tactics to help the resistance against the returning threat.
It could be a young Imperial officer who starts to question the Empire's extreme measures for revenge. This character might see the wrong in what the Empire is doing and eventually defect to the Rebellion.
Darth Vader is often a main character. His menacing presence and complex character make him a favorite to explore further in fanfiction. Writers can delve into his inner thoughts and his relationship with the Emperor.
It could be an ordinary human on Earth who rises to become a hero against the Empire. Maybe a scientist who figures out a way to counter the Empire's force powers.
One idea could be exploring what would happen if the Empire experimented with cloning Jedi. They might try to create Jedi - like soldiers under their control.
One of the main characters is an Imperial pilot. There are often squadron leaders who play important roles. They are in charge of leading their fellow pilots into battle. Another could be Imperial officers who give out orders and strategize.
The main character is Kir Kanos. He is the central figure around which the story revolves.