A story could start with Starkiller being on a mission for the Empire and Ahsoka getting wind of it. She decides to stop him. Their paths cross on a desolate planet, and there's an immediate tension as they size each other up, not knowing fully what the other is capable of.
It could begin with Ahsoka sensing a disturbance in the Force. This disturbance leads her to Starkiller. He's in a situation where he's being hunted by some other dark side entities. Ahsoka, being the one who senses his conflict (between his powers and a possible path to redemption), decides to help him. This starts their journey together, with both having their own motives and secrets.
Maybe the story starts at a cantina. Starkiller is there undercover for some reason related to the Sith plans. Ahsoka enters the cantina as well, looking for information. They notice each other's unique auras in the Force. Starkiller is intrigued by Ahsoka's presence and Ahsoka is immediately on guard. This chance encounter sets off a chain of events that draws them into a complex adventure together.
In an alternate universe, Starkiller and Ahsoka could be comrades. They might team up to fight against a greater threat in the galaxy. Maybe they meet during a mission where they initially have their doubts about each other but gradually learn to trust and rely on one another.
Starkiller is the central character in this story. He's likely to be a character with unique abilities and a significant role in the Star Wars universe.
He's often portrayed as a powerful and mysterious figure. Writers in fanfiction may show him using his Force abilities in creative ways that we don't see in the main Star Wars canon related to Star Wars Rebels. He could be a force for good, despite his past, and his presence might inspire the Rebels to take bolder actions against the Empire.
One way to integrate Starkiller into the Clone Wars in fanfiction is to make him a time - traveler. He could be sent back in time to the Clone Wars era, and his knowledge of future events could cause all sorts of chaos. He might try to prevent certain tragedies from happening, like the fall of the Jedi Order, which would put him at odds with the Sith who are plotting those very events.
Their relationship could start with mutual respect due to their Jedi training. As they go on adventures together, they'd grow to trust each other more. For example, in a fight against the Empire, Ezra might save Ahsoka's life, deepening their bond.
If Ahsoka dies in fanfiction, it would have a huge impact on her friends. Anakin, for example, would be deeply affected. He already lost his mother and has a fear of losing those close to him. Her death could potentially drive him further towards the dark side as he grapples with grief and anger. Her presence has always been a positive influence on him, and without her, he might lose some of his moral compass.
Starkiller can be a game - changer in Star Wars crossover fanfiction. He can bring his combat skills and Force knowledge to new settings. For example, if he's in a crossover with the Matrix universe, his ability to sense and manipulate the Force could be compared to Neo's ability to control the Matrix.
In the era of the Old Republic, Starkiller's abilities would be quite different. The Force was more in tune with the natural order then. His raw power might be more subdued as he would have to adapt to the more traditional ways of the Jedi and Sith. For example, his lightsaber combat might become more refined in the style of the ancient Jedi, rather than his more aggressive style from his own time.
First, research both characters well. Know Starkiller's powers and his backstory, and also understand Padme's role in the Star Wars universe. Then, think of a unique plot. It could be something like Starkiller is sent on a mission that involves protecting Padme. Start with a strong opening that grabs the reader's attention, like a sudden attack on Padme that Starkiller has to fend off.
One possible fanfiction could be about Rex and Ahsoka going on a secret mission together. They might face a new and dangerous enemy that the Republic has not yet encountered. Rex would use his military tactics and Ahsoka her Jedi skills to overcome the challenges.