It's hard to say for sure without reading it, but it could still be Bella, Edward, and Jacob. Since it's a Twilight fanfiction, they are likely to be important. Maybe it focuses on how they react when things start to go wrong in the downward spiral.
It could be about the Twilight world going through a downward spiral in general. This could mean the collapse of the treaty between the vampires and werewolves, leading to chaos. Or perhaps the Volturi's actions causing a chain of events that sends the world of Twilight into a downward spiral. Fanfiction often takes the existing world and characters and twists them in new and unexpected ways, and this title might suggest a story that does just that to the Twilight setting.
It might feature some of the original Hunger Games characters but with different personalities or motives in this fanfiction. For example, Katniss could be portrayed in a more conflicted way, struggling not only with the games but also with the new challenges in this downward spiral scenario. Another could be a completely new character created by the fanfiction writer, like a young rebel who has a different perspective on the whole Hunger Games system.
Since we don't have much information about this 'time spiral novel', the main characters could be ordinary people who get caught up in the time - spiraling events. They might start off as normal individuals living their regular lives, but then as the time - spiral begins to affect their world, they develop unique abilities or characteristics related to dealing with time. For example, one character could be able to remember fragments of different time loops, which helps them try to break free from the spiral or understand it better.
I don't know for sure since I haven't read it. But typically in such a novel, there might be a curious protagonist who is drawn to the spiral staircase, perhaps a young person full of inquisitiveness.
I don't know since I haven't read it. It could be a single protagonist on a solo journey downward to the earth, or it might have a group of diverse characters with different skills and personalities.
One interesting plot could be the main character trying to form an unexpected alliance within the arena. This alliance might consist of characters who were originally enemies, adding a lot of drama and strategic elements to the story.
Communication in her marriage is key. If she can openly talk to her husband about their problems, whether it's financial, emotional or something else, they can work together to find solutions. Instead of feeling alone and desperate, she can feel like she has a partner in dealing with life's challenges, which would prevent her from taking such a drastic step as turning to prostitution.
In many stories of this kind, there might be a leader among the Black Spiral Dancers. This leader would be a main character, driving the actions and decisions of the group. Additionally, if there are other groups in the story, their leaders or representatives could also be main characters. For example, a wise old sage who tries to stop the Black Spiral Dancers' chaos, or a young hero who discovers their existence and decides to take a stand against them.
The main characters are likely to be the ones from the original 'Twilight' like Bella, Edward, and Jacob. In fanfiction, they might be portrayed in different lights or with different personalities.
Since I don't know the exact story, it's difficult to say. But presumably, the Black Spiral Dancer is one of the main characters. There may also be other characters like scientists if the nuclear aspect involves research, or maybe some sort of authority figures trying to deal with the situation created by the Black Spiral Dancer.