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.
The main characters could be the Fire and Ice Pokemon themselves. For example, a Flareon and a Glaceon. They could be on a quest to find a special crystal that can balance the power of fire and ice in their world. Their interactions and growth throughout the journey would be the focus of the fanfic.
It could be a new character, an ice ninja named Hakuji. He has a tragic past, his family was killed by a rogue ninja group and he was left alone in the cold northern lands. He comes to Konoha seeking revenge at first but then befriends Naruto and changes his path.
Well, there could be the dragon lords. One might be a powerful fire dragon lord who is fierce and protective of his kind. And on the ice side, a wise ice dragon lord who is known for her strategic thinking.
Maybe a story where the Cullen family in 'Twilight' has to deal with an invasion from the world of 'Fire and Ice'. The White Walkers could pose a threat to their way of life, and they would have to use their vampire and werewolf allies, along with their own unique abilities, to fight back. Or perhaps a love story between a character from 'Fire and Ice' and one from 'Twilight', like Jon Snow falling in love with a vampire or a werewolf. This would bring a whole new level of drama and cultural clash to the fanfic.
The main characters could be a young, inexperienced trainer who has just caught their first Fire - type and Ice - type Pokemon. As they journey through the Pokemon regions, they learn about the strengths and weaknesses of their Pokemon, and grow as a trainer. Along the way, they meet other trainers and Pokemon that help or hinder their progress. For example, an older, more experienced trainer who tries to convince the young trainer to give up their Ice - type Pokemon because it's 'too weak' in their opinion.
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.
It could be a Gryffindor student. Gryffindors are known for their bravery, and sometimes that can lead to them taking risks that are like playing with fire. Maybe a young Gryffindor who is overconfident and gets into trouble by trying to prove themselves.
Naruto himself could be a main character. He has a natural inclination towards befriending powerful beings, and his determination would make him a great fit to interact with the fire and ice dragons. Sasuke could also be a main character, with his Sharingan potentially having some unique interactions with the dragons' powers.
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.