It might be an entirely new character made up for the fanfic. This character could be a powerful Sith Lord who has a family or is in a father - like role to other Sith. He would be a source of dark power and influence within the story.
Another aspect to consider is that the 'Dark Father' could be a metaphorical concept in the fanfic. It could represent the dark influence that pervades the Star Wars universe, like the overarching power of the Dark Side. This could be personified as a father - like entity that is constantly pulling characters towards the path of darkness.
Another option could be a hybrid character. Maybe a half - Dark Angel, half - Star Wars species character. This character would be constantly torn between the two sides of their heritage, having to decide whether to embrace their Dark Angel side, which might be more about physical strength and survival, or their Star Wars side, which could involve the moral choices related to the Force.
Redemption is a big one. Fans often explore how Darth Vader can be redeemed through his relationship with Luke. Another theme is the power of family. It shows that even in a galaxy far, far away, the bond between father and son can be a powerful force. And the theme of legacy is also common. It's about how their relationship will shape the future of the Skywalker family and the Jedi.
One common theme is the passing down of values. In the Star Wars universe, fathers often pass on their beliefs about the Force, good and evil, etc. to their sons. For example, a Jedi father might teach his son about the importance of using the Force for good. Another theme is redemption. If the father has made mistakes in the past, the son may play a role in his redemption, like in some fanfics where a Sith father is redeemed through his son's love and guidance.
As there is no official 'Dark a Star Wars Story', it's difficult to say who the main characters would be. But if it were a dark - themed story, it might feature Sith lords like Darth Vader or Darth Maul as central characters, as they represent the dark side of the Force in the Star Wars universe.
Revan is a significant character in some of these novels. He has a very complex backstory, having once been a Jedi and then falling to the dark side and back again. Also, characters like Darth Sidious play a major role as they are often the main antagonists in the 'dark' storylines.
There could be a fanfic where an ancient Dark Side artifact is discovered near the Ghost. The crew decides to study it, not realizing the danger. As they do, the Dark Side energy starts to affect the ship itself. Systems malfunction, and strange things start to happen. Kanan, with his Jedi knowledge, tries to figure out how to neutralize the artifact and save the Ghost from being consumed by the Dark Side.
In the 'Star Wars The Clone Wars Dark Disciple Novel', it's possible that the main characters include those involved in the Clone Wars machinery. There could be a Jedi master who is trying to stop the rise of the 'Dark Disciple'. The 'Dark Disciple' themselves would be a central character, whose actions and choices drive the plot. There might also be supporting characters like senators or other Force - sensitive beings who are caught in the crossfire of the conflict between the light and dark forces during the Clone Wars.
Another popular fan theory is that Han Solo could be the father. Their past relationship in Qi'ra's backstory makes it a plausible scenario. If Han is the father, it would create a lot of emotional turmoil for Qi'ra. She would have to deal with her feelings for Han, as well as the reality of raising a child in a galaxy where Han is constantly on the run from various threats, including the Empire.
The main characters include Luke Skywalker, Emperor Palpatine, and Leia Organa. Luke has to face Palpatine's new threat, and Leia is involved in the political and military affairs of the New Republic.