Well, in a fanfic where Anakin beats Obi - wan, it might be due to Anakin's raw power potential finally being fully unleashed. Anakin had incredible Force abilities that were often held back by his internal conflicts. In this fanfic scenario, perhaps he overcame those conflicts in a different way, allowing him to focus all his power on the fight against Obi - wan. Also, external factors like the environment could play a role. If the battleground was more favorable to Anakin's fighting style, it could give him the upper hand.
One key element is a change in Anakin's character development. He might have a different mental state, more focused and less conflicted. Another element could be a new combat style for Anakin. Maybe he combines his lightsaber skills with some unique Force maneuvers. The setting of the fight also matters. If it's in a place that Anakin is more familiar with, it gives him an advantage.
In many fanfictions, Obi - Wan might use his deep knowledge of the Force. He could reach out to Anakin through a Force - bond, calming his inner turmoil and guiding him away from the dark side. For example, he might remind Anakin of their past together, their training, and the values they once held dear.
One possible reason could be that Anakin taps into a new, darker power source. Maybe he discovers a hidden Sith ability that gives him an edge over Obi - Wan's more traditional Jedi skills.
Maybe the Force itself could be an antagonist in a sense. The light side of the Force would be trying to pull Obi - Wan back from the dark side. And the natural balance of the Force that doesn't want too much dark side influence could be working against Anakin's plan to turn Obi - Wan. So the Force, in its own way, could be the main antagonist.
Well, 'The Unspoken Understanding' is a must - read 'anakin obi wan fanfiction'. It focuses on the unsaid emotions and the silent communication between the two. It beautifully portrays their friendship and the trust that was once there. Also, 'Anakin and Obi - Wan: Parallel Journeys' is really good as it shows their individual growth while still being connected to each other.
Perhaps Obi - Wan uses his Jedi skills in a creative way. For example, he could use a Force - related technique that shields Anakin from the influence of the Sith. He might create a sort of Force barrier around Anakin's mind, preventing the dark whispers from corrupting him further.
Another theme is the struggle between the light and dark side of the Force. Since Anakin eventually turned to the dark side, fanfics like to play with this idea. They might show Obi - Wan trying to bring Anakin back to the light, or Anakin trying to convince Obi - Wan that the dark side has its merits in certain situations.
Sure. In some fanfictions, a female Obi - Wan could have a more complex relationship with Anakin. Maybe she has to deal with the same challenges as the male Obi - Wan in the original, like Anakin's struggle with the dark side, but in a different way because of her being female. This could lead to some really interesting character developments and plot twists. Additionally, the way they communicate and interact with other characters in the Star Wars world might also change, making for a fresh take on the story.