One possible plotline could be Nightwing struggling to fill Batman's shoes in Gotham. He might face challenges like dealing with more dangerous villains who see him as a new target. Another could be his relationship with the other members of the Bat - family changing as he takes on the Batman mantle.
Obviously, Nightwing himself would be the main character as he's the one taking on the Batman role. Robin, if there's a younger Robin at the time in the fanfiction, would also be a key character. He might look up to Nightwing in his new role or have some doubts about him filling Batman's shoes.
One common aspect in these fanfictions is the struggle with identity. Robin has been known as Batman's sidekick for so long. Becoming Nightwing means carving out his own path. He has to deal with how his friends in Young Justice will view him. Some might be supportive right away, while others may be skeptical at first. His costume change also symbolizes a shift in his role within the team and the wider superhero community.
Well, a 'deadman switch novel' might refer to a book that features a deadman switch device or concept. In many cases, this could involve a mechanism that is activated or deactivated upon the death or incapacitation of a person. It could be used in various genres, like science fiction if it's a high - tech deadman switch in a futuristic setting, or in a crime novel where it has something to do with illegal activities.
One possible fanfic could involve a battle against a powerful villain. Nightwing might get injured while trying to protect Gotham. Batman then has to step in not only to defeat the villain but also to take care of Nightwing. He could use his advanced medical knowledge and resources in the Batcave to nurse Nightwing back to health.