It might be a newly - turned vampire who is struggling to control their thirst and is hiding in the shadows to avoid detection while preying on humans. This character could be conflicted between their new nature and any remaining human morality, which makes them a complex and dangerous 'killer in the shadows' figure in the Twilight fanfiction.
Perhaps it's a human who has somehow discovered the existence of vampires and werewolves and has decided to take matters into his own hands, using his knowledge of the town's layout and the creatures' weaknesses to become a killer in the shadows. He might be motivated by a desire to protect the town from what he sees as a threat, but his methods are extreme.
It could be about a mysterious and dangerous character in the Twilight universe who lurks in the shadows. Maybe it's a new vampire or some other supernatural being that poses a threat to the main characters in the Twilight world.
Well, it could be a new vampire that the author has created. This vampire might be a loner, living in the shadows away from the main vampire clans in Twilight. Another could be a human character who stumbles upon this hidden vampire world.
It depends on the specific fanfic, but often it will include the main characters from the Twilight series like Bella, Edward, and Jacob. However, the fanfic might focus more on their actions and personalities in the'shadows' context, so they could be portrayed with different motives or characteristics compared to the original.
Perhaps a plot where a werewolf, instead of being an enemy of vampires in the Twilight universe of this fanfiction, forms an alliance with a vampire living in the shadows. They work together to protect their territory from a common threat that the Cullens are unaware of.
The unique blend of the Yugi universe with the concept of twilight shadows. It's not something you see in the original series often. The fanfiction writers get to explore new, darker aspects of the characters and their world.
Perhaps a young wizard or sorceress. They would have the magical abilities to detect the demon's magic and might be in a unique position to combat it. Their inexperience could also add an interesting dynamic as they learn more about the demon and their own powers in the process.
One great 'Dark Shadows' and 'Twilight' fanfiction might be one that combines the gothic elements of 'Dark Shadows' with the supernatural romance of 'Twilight'. For example, a story where a character from 'Dark Shadows' visits Forks and gets involved in the vampire - human drama there. Another could be a story that explores how the different vampire rules in both universes interact when characters cross over.
It could be a rogue ninja who has risen to power within the League of Shadows. This ninja might have a personal vendetta against Naruto or the Hidden Leaf Village and uses the resources of the League of Shadows to carry out his or her revenge.
It could be a rogue ninja who has a personal vendetta against Naruto. Maybe someone from his past that he thought was defeated but has now returned with new powers and a thirst for revenge.
It could be Orochimaru. He's always been interested in new and powerful jutsus. He might see Naruto's shadow - controlling ability as something he wants to steal or use for his own evil purposes.