Since we don't have any information about the specific plot or source material of this fanfiction, it's difficult to say who the main characters are. They could be everyday people who find themselves drawn to the mystery of the one dark window, or they could be more fantastical characters if it's set in a fictional universe. Maybe there's a brave explorer who wants to uncover what's behind the dark window, or a curious child who gets caught up in the strange events associated with it.
I don't know for sure as I haven't read it. But it could be original characters created by the fanfiction writer, or it might feature characters from the original work it's based on.
I'm not entirely sure specifically as it could be various things. Fanfiction often takes existing works and expands on them in new and creative ways. It might be a fan - created story related to a work with the theme of a 'dark window', perhaps in a horror or mystery context.
Obviously, the Dark One is a main character. Harry Potter himself also often plays a crucial role as he is usually the one who has to face the Dark One in some way.
There's no way to tell precisely without more details about the story. However, it's common in such stories to have a protagonist who is facing the events of the dark night. This could be a young person, like a teenager who sneaks out at night and then has to deal with whatever comes their way. Or it could be an adult with a secret who is out on a dark night and things start to go wrong.
In dark One Piece fanfiction, Enel is sometimes a very popular character to explore. Given his god - complex in the original story, it's easy to make him an even more menacing and all - powerful figure in a darker version. Crocodile is another one. His past and motives can be delved deeper into, and he can be made into a more complex and dark character. Buggy the Clown can also be a popular character, especially if his comical nature is turned on its head to make him a more devious and unpredictable villain.
Snow White and Charming could play important roles in interacting with Regina. They've had a long and complicated history with her. In this fanfiction, they might initially be distrustful of her as the Dark One, but as the story progresses, they could see that she's still the Regina they know and try to find a way to help her. Also, Rumplestiltskin, being a former Dark One himself, could interact with Regina, perhaps mentoring her in some way or warning her about the dangers of the dark power.
There could be other magical beings as well. Maybe the wizard who might know something about the Dark One's power and how to reverse it. Also, Henry's friends like Violet could play a role. They might be initially scared of him but then decide to help him because they believe in the good in him still. And don't forget about Hook, who has experience with dark magic and could either be an ally or an adversary depending on the story's direction.
Since it's fanfiction, the author has the creative freedom to introduce all kinds of characters. It could be a group of misfits, and the main character, the beacon in the dark, could be an outcast among them who eventually shows them the way forward. Or it could be a story centered around a mentor - like figure who is the beacon for a younger generation of characters trying to find their place in a complex and often dangerous fictional world.
Since I don't know the exact 'the dark gamer fanfiction', it's hard to say for sure. But it could be the gamer themselves as the main character, who might be an outcast in the real world but a force to be reckoned with in the game world. There could also be a mentor - like figure who guides the gamer through the dark aspects of the game, or an antagonist who tries to stop the gamer from achieving their goals in this dark gaming journey.
Obviously, Dark Bonnie is a main character. He is often depicted as a menacing and mysterious figure. Other characters can include Freddy, Chica, and Foxy from the same animatronic group. They are usually in conflict with Dark Bonnie in some way.
Perhaps there are heroes or anti - heroes in the 'the dark goddess fanfiction'. They could be characters who oppose the dark goddess, trying to stop her from achieving her goals, whatever they may be. And there could be other deities or powerful beings who interact with the dark goddess, either as allies or enemies, and they would also be main characters.