Medical droids can be main characters too. They are the ones in charge of operating the Bacta tank. A fanfic could tell the story from the perspective of a medical droid, showing how it deals with different patients in the Bacta tank, the challenges it faces in maintaining the tank, and its relationship with the living beings it heals.
Maybe a story where a group of rebels discovers an ancient Bacta tank with unique properties. They have to figure out how to use it to heal their critically injured comrades while being chased by the Empire. This would involve elements of adventure and survival.
For a character who has been healed in a Bacta Tank, their development could start with a sense of newfound gratitude and a changed perspective on life. For example, a battle - hardened soldier might come out of the tank with a new resolve to end the war through peaceful means.
Often, Imperial officers are main characters. They are shown as being in charge of the Empire Day arrangements and making sure everything goes according to plan. For example, Grand Moff Tarkin might be overseeing the construction of a new monument for Empire Day on a conquered planet.
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.
Darth Vader is another main character. His menacing presence and his fall from grace as Anakin Skywalker are important aspects of the Star Wars lore. In the '5 minute star wars stories', his battles and his relationship with the Emperor might be told.
The clones are often main characters. They are the ones who execute Order 65, so fanfictions explore their motives and feelings. Some clones might be remorseful, while others are just following orders blindly.
In the Star Wars universe, Darth Vader was often in need of healing. The Bacta tank was a crucial device for that. Darth Vader, after many battles and injuries, might have used the Bacta tank to soothe his pain. It was a place where his damaged body could be mended. The Bacta fluid would surround him, and while in there, one could imagine him reflecting on his dark path and his loyalty to the Emperor.
Obviously, Surik herself is the central character. She is the focus of these stories.