Luke Skywalker is often a popular character. His journey from a simple farm boy to a powerful Jedi knight makes him a prime focus. Also, Darth Vader, with his complex backstory and his struggle between the light and dark, is frequently featured.
Darth Vader is sometimes used in an interesting way in these fanfictions. Even though he's a symbol of the dark side, some fanfictions might explore a sort of unrequited love or a complex relationship where someone in the Empire has feelings for him, perhaps seeing the conflict within him that others don't. It adds a dark and complex layer to the romance.
Luke Skywalker is also commonly featured. As the hero of the original trilogy, his journey and growth in the Force make for interesting battles, whether he's facing off against Sith or other threats in the fanfiction Death Battle settings.
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.
Clone troopers are often main characters. Since Umbara was a significant location in their story arcs, fanfiction might focus on their experiences, like Captain Rex leading his troops through the dangerous terrain and battles on Umbara.
Jedi are often main characters. Jedi like Obi - Wan Kenobi or Yoda might be the focus as they deal with the aftermath of Order 66. Also, clone troopers are common. Some fanfictions might feature a particular clone who has a change of heart during Order 66.
One common theme could be the exploration of a knight's moral dilemmas. In Star Wars, knights often face tough choices between the light and dark side. Another theme might be their relationships, like a knight's loyalty to their comrades or their romantic interests within the Star Wars universe.
Rey is a very popular character in these fanfics. Her mysterious origin and powerful Force abilities make her a great subject for exploration. Kylo Ren is also often featured. His conflicted nature between the light and dark side is fascinating to write about. Finn is another one. His journey from a Stormtrooper to a Resistance fighter can be further developed in fanfic. And of course, Luke Skywalker, as he is such an iconic character in the Star Wars saga and his role in The Last Jedi can be reimagined in many ways.
Obviously, Surik herself is the central character. She is the focus of these stories.
Some fanfictions in 'Brothers in Arms Star Wars' focus on new, original characters. For example, a young Jedi trainee and a smuggler who cross paths. The Jedi trainee is on a quest to find a lost Jedi artifact, and the smuggler has information about its whereabouts. As they journey together, they become brothers in arms, facing pirates, Sith assassins, and other perils.
Darth Vader also features a lot. There could be stories that go deeper into his past, perhaps his time as Anakin before he fully embraced the dark side. It could show his internal struggles in a new light.