Definitely Naruto is a main character. There might be some antagonists that are drawn to the power of the Dark Phoenix within Naruto. These could be new villains created for the fanfiction. And Naruto's teacher Jiraiya might also be involved if the story delves into Naruto's search for understanding and controlling the Dark Phoenix power, as Jiraiya was always there to guide Naruto in the original series.
The hunter is obviously a main character. They are the ones who brave the dark and face the unknown. Another could be the various creatures of the dark that they encounter, which can be considered as important characters as they drive the action.
Often, the Nine - Tails within Naruto can be considered a main character in a sense in these fanfictions. Since the phoenix power might interact with the Nine - Tails chakra, the Nine - Tails' personality and power are crucial elements. Additionally, villains are also main characters in a way, as they are the ones who oppose Naruto's growth with the phoenix powers and try to use it for their own evil purposes.
Obviously Naruto is the main focus most of the time. But other characters like Sasuke can also be important. Sasuke's own dark past and his relationship with Naruto can be further explored in a 'dark' context. For example, they might become rivals in a more extreme and less friendly way.
It depends on the specific fanfiction. However, often there are characters that are associated with the themes of 'dark blue' and'moonlight'. Maybe a brooding hero type who is often seen in the dark blue of night or a mysterious figure that appears under the moonlight.
Sometimes, there could be new characters introduced in 'dark willy wonka fanfiction'. For example, a rival chocolatier who tries to expose Wonka's dark secrets. This character could add more conflict and drama to the story, as they fight against Wonka's empire of chocolate, which has some hidden and not - so - nice aspects.
Typically, there is a 'Papa' character who is likely to be a central figure. There might also be a younger character with whom the Papa has some sort of relationship. But it really depends on the specific fanfiction as different writers may create different main characters.
Often, the main character is a human or some other non - dark elf race who gets captured. Then there are usually the dark elves themselves, with their leaders or powerful warriors being important characters. Maybe there's a dark elf princess or prince who has a role in the captive's fate.
In 'King Dark Yaoi Fanfiction', the main characters usually revolve around King Dark, who is often portrayed as having a strong and imposing presence. The second main character is usually someone who is different from the king in some way. It could be a gentle healer who softens the king's hard exterior. Or it could be a rebellious thief who challenges the king's authority and in the process, a romantic relationship starts to develop between them.
Obviously, Bella is the main character. In most of these fanfictions, Edward might also be there, often having to deal with this new, dark and powerful side of Bella. Jacob could also be involved, sometimes as an ally and sometimes as an adversary to Bella's new self.
The main characters are often Naruto, as he is the focus of the mecha concept. Shikamaru could also be a main character in this type of fanfiction. He would be the strategist, trying to figure out how to best utilize the mecha Naruto in battles. Additionally, Orochimaru might be a character in some cases. He could be interested in stealing the technology of the mecha for his own evil purposes or trying to manipulate Naruto through it.