The main character being the second son in the 'the second son twilight fanfic' could be a variety of things. It could be a long - lost son of one of the major Twilight characters. For example, if it's a vampire family, he might be the second son who has been hidden away for some reason and now resurfaces, causing chaos or a new dynamic within the family. Or it could be a werewolf second son who has different abilities compared to his pack mates and his story could revolve around how he uses those abilities, his relationships within the pack, and how he deals with the presence of vampires in the area as per the Twilight lore.
I'm not sure specifically as there could be many different interpretations of a 'Twilight' fanfic about the second son. It might focus on a character who is the second son in the Twilight universe, perhaps exploring his relationships, powers, or his role within the vampire or werewolf clans.
One possible fanfic could be about the second son of a duke in the Twilight universe trying to find his place among the vampires and werewolves. Maybe he has a unique power that sets him apart from others. He could be caught in the middle of the eternal feud between the two groups, struggling to decide which side he should be on, or if he should try to create his own path.
Edward could also be the main character. He has his vampire senses which could help him analyze the bloody fingerprints in ways humans can't. He might be on a mission to protect Bella and the rest of his family from whatever danger the fingerprints signify. Maybe he suspects that it's a new threat from a nomadic vampire group and he has to use his skills to track them down.
Maybe it's a side character from the original Twilight books that the writer decides to give more depth to. Like one of the lesser - known vampires in the Volturi coven who has a secret past and motives that are explored in the fanfic.
Arya Stark from 'Fire and Ice' could be a great main character in a 'Fire and Ice Twilight Fanfic'. She has the skills of a trained assassin and a strong will. In the fanfic, she could find herself in the world of 'Twilight' and use her skills to navigate the dangerous world of vampires and werewolves. Maybe she would form an alliance with the Cullens or the werewolf pack and help them in their battles.
I'm not entirely sure as it's a fanfic, but it could include the main characters from the Twilight series like Bella and Edward. They might be involved in the events around the twilight lagoon, perhaps exploring it or having some kind of encounter there.
It could be Renesmee. Since she has a connection with Jacob in the Twilight series, it's not a stretch to think that they might end up having a child together in a fanfic. Their relationship was already quite complex and a child would add another layer of depth to it.
He could have an adventure where he tries to broker peace between the vampires and werewolves. Given his noble status as the second son of a duke, he might have the influence and diplomatic skills to attempt such a feat. He could travel between the two camps, facing hostility from some members who are more set in their ways of the eternal conflict.
It could be a woman who was once an ordinary Twilight fan but then became a trophy wife. So she brings her Twilight obsession into her new life. She might be someone who is constantly trying to balance her love for Twilight with her new - found status as a trophy wife. For instance, she may try to incorporate Twilight - related items or themes into her luxurious lifestyle.
There's also a possibility that it could be a self - insert of the author. In this case, the author imagines themselves living in the Twilight world and having the ability to redo certain situations, which would make them the main character driving the new narrative in this fanfic.