One interesting plotline could be a battle that takes place in an alternate universe where Anakin and Obi - Wan have different allegiances from the start. Maybe Anakin is a Sith Lord right from the beginning and Obi - Wan has to face his former apprentice in a more cut - throat battle.
Anakin and Obi - Wan could fit into a Marvel fanfic if they were part of a multiverse - spanning story. The Marvel universe already has concepts like the multiverse. They could be brought in as representatives of a different kind of power (the Force). Anakin's emotional and sometimes unpredictable nature could create interesting dynamics with the more stable Marvel heroes. Obi - Wan could act as a mediator between the two universes, using his knowledge of the Force and his diplomatic abilities to navigate the complex relationships in the Marvel world.
Well, Anakin is often very well - written. His internal conflict between the light and dark side can be explored in great detail. His complex relationship with Obi - Wan, from being a beloved apprentice to a bitter enemy, gives a lot of room for character development. Writers can show his journey from a hopeful Jedi to a conflicted individual on the verge of falling to the dark side.
In some fanfics, there might be a plotline where Palpatine tries to corrupt Anakin even further during the battle, using psychological warfare. Anakin, on the other hand, has to resist this while also fighting for his life. This adds a layer of psychological drama to the physical fight between them.
Well, it could be really chaotic. Maybe Anakin and Obi - Wan would be mistaken for new superhumans in the Marvel universe. Their lightsabers would be seen as some sort of high - tech weapons. They might end up getting involved in the Avengers' battles, either as allies or foes depending on how the story is written. Anakin's power could be compared to that of Scarlet Witch, and Obi - Wan's wisdom might be on par with Doctor Strange's.
It really depends on how the author writes it. If the fanfic focuses on Anakin's potential and his growth beyond what we saw in the movies, he could win. For example, if he has fully mastered some new form of lightsaber combat or Force ability.
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.
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.