One possible plot could be Jason Todd's struggle to maintain his sanity within Arkham Asylum. He might be haunted by his past traumas and face off against the various villains locked up there. Maybe he's trying to find a way to escape while also dealing with the asylum's staff who may or may not have their own hidden agendas.
The Joker could be a main antagonist. Given his history with Jason Todd, he might try to further torment him in Arkham. He could play mind games with Jason, trying to break his already fragile mental state.
Well, there's a fanfiction called 'Jason Todd: Beyond the Arkham Knight'. In this story, Jason tries to find his own identity separate from the labels of Arkham Knight and Robin. It has some really cool action scenes and also explores his friendships and enmities in Gotham. And then there's 'Arkham Knight's New Path' which is about Jason forging a new, more positive path for himself in Gotham.
In Arkham Knight fanfiction, a Jason Todd OC might have unique abilities or a backstory that ties into the Arkham Knight's world. Maybe the OC has a connection to the criminal underworld in Gotham that Jason can use to his advantage in his fight against crime. It could also be that the OC is a scientist who helps Jason with some of the tech - related challenges he faces.
In a 'Danny Phantom in Arkham Asylum' fanfiction, Danny could be brought to Arkham by some sort of interdimensional rift. Once there, he might find that some of the inmates have a connection to the ghost zone that he didn't expect. For example, Scarecrow's fear toxins could have an unexpected reaction on Danny due to his half - ghost nature. Danny would have to use his wits and powers to survive in this new and dangerous environment. He could also form an unlikely friendship with a reform - minded inmate who helps him understand the asylum's inner workings and how to find a way back to his own dimension.
I really like 'Jason Todd's Return: Arkham Knight's Hidden Story'. This fanfic focuses on Jason's role in the Arkham Knight events from a different perspective. It shows how he might have been feeling during all the chaos, and it gives a more sympathetic view of his actions. It's a shorter read but still packs a punch in terms of character exploration.
One of the main reasons is the potential for character growth. Jason Todd has had a rough journey, and in Arkham Knight fanfiction, we can see him evolve. Maybe he overcomes his hatred for Batman, or he becomes a better hero. Also, the Arkham Knight setting is so rich. The dark and gritty atmosphere of Gotham in that universe provides a great backdrop for stories about Jason. There are so many elements like the other villains, the technology, and the city's layout that can be used to create interesting and engaging fanfiction about him.
One possible plot could be Harry exploring the dark secrets of Arkham Asylum. He might encounter various infamous inmates and try to survive their threats while also uncovering a conspiracy within the asylum's walls.
The plot could involve Percy arriving at Arkham Asylum, perhaps as a new patient or a visitor. He might encounter various iconic villains from the Arkham universe and have to navigate the dangerous and chaotic environment. Maybe he has a special ability or knowledge that makes him stand out among the inmates and staff.
When creating a Jason Todd OC for Arkham Knight fanfiction, start with a strong backstory. Consider what events in their past led them to cross paths with Jason. It could be something as simple as growing up in the same rough neighborhood.
The popularity of 'Batman: Arkham Knight' Jason Todd fanfiction lies in the character's complexity. Jason has a tragic backstory - being killed and then resurrected. Fanfiction writers can explore his journey of redemption or revenge. For example, in many stories, we see him struggling with his identity, which is a very engaging theme.