The obvious main characters could be the leaders of the Dark Knights themselves. They are the ones driving the actions and decisions of the group.
A human sorcerer who has joined forces with the Dark Knights could also be a main character. He could bring a different perspective, being a human in a group mainly made up of other races perhaps. He might be using the Dark Knights for his own gain, like seeking immortality through their dark magic. His complex motives and actions would make him an interesting main character.
The modern girl, of course, would be one of the main characters. And probably a well - known Middle - Earth character like Aragorn. He could be her guide in the new world she has found herself in. Maybe Gandalf would also play an important role, being interested in this strange girl from another time.
Perhaps the Dark Knights could be on a quest to find a long - lost artifact that would give them ultimate power. Along the way, they face challenges from various Middle - earth races who oppose their goal. This could lead to epic battles and unexpected alliances. For example, they might encounter elves who are protecting the location of the artifact, and a complex power struggle ensues.
The Joker is a character that can't be ignored. His chaos - loving nature and his long - standing enmity with Batman would make for great drama in the fanfiction. Then there's Commissioner Gordon. He represents the law in Gotham and his partnership with the Dark Knights, especially Batman, is crucial. Also, Nightwing, who was once Robin and has his own set of skills and a different way of operating in Gotham compared to Batman.
It could be a young hobbit who discovers a hidden power within himself. Hobbits are not typically known for great power, so this would be an interesting twist. He could be fated to use this power to save Middle Earth from a new and unknown evil.
I don't know as I haven't read it. Maybe there's a brave hero or heroine who leads the story.
There are reimagined versions of classic DC characters like Superman, Batman, and Wonder Woman, among others.
Arwen is often a popular character in Middle Earth fanfiction, even though she's from the original lore. Writers might expand on her story, like her life before she met Aragorn. Another could be a completely new girl character created by the fanfiction author, perhaps a young healer who travels with the rangers and helps the wounded.
An ancient and malevolent spirit that has been awakened in Middle Earth. This spirit is angry at the living beings for disturbing its slumber and decides to target the little white knight specifically. It has powers that are difficult to understand and combat, and it uses fear and chaos to try to break the knight's spirit and stop him from fulfilling his purpose in Middle Earth.
Sauron could be a major antagonist. His power and desire for domination would put him in direct conflict with Harry. Voldemort - like elements might be incorporated into Sauron's character in this fanfiction.
Talion and Celebrimbor are the central characters in Middle Earth: Shadow of War story. Talion is a human ranger who got entwined with Celebrimbor's spirit. Celebrimbor is an important figure from the past with great knowledge and power. Their partnership is crucial in the fight against Sauron and his forces.