In fanfiction, their relationship could be one of mutual respect despite their differences. They recognize each other's power and abilities. The Dark Avatar might admire Korra's determination to protect the world, and Korra could respect the Dark Avatar's knowledge of ancient and dark arts. This could lead to a series of encounters where they test each other's limits, not always in a hostile way, but more in a way of trying to understand the other better.
The relationship could be shown as a mentorship of sorts in fanfiction. The Dark Avatar, having a different perspective on power and the spirit world, could teach Korra things she never knew. At the same time, Korra could try to reform the Dark Avatar. It would be a complex relationship full of give - and - take, with both characters growing in different ways. For example, the Dark Avatar might learn about compassion from Korra, while Korra could learn about the hidden aspects of the spirit world from the Dark Avatar.
Characters from the spirit world, such as Raava and Vaatu, might also be popular in Korra Dark Avatar fanfiction. Since the concept of the Dark Avatar is closely related to the balance between light and dark in the spirit world, these spirit entities can be used to drive the story forward, either as allies or foes of the Dark Avatar.
The relationship could be shown as a mentor - mentee type in some fanfictions. Maybe the Dark Lord, in an alternate reality, decides to teach Harry some of his dark magic knowledge not to corrupt him, but to make him stronger to face other threats in the wizarding world. This would completely change the dynamic between them. They could also be shown as reluctant allies, forced to work together to stop a greater evil that is emerging in the wizarding world. This would involve a lot of tension and distrust between them at first, but gradually they could start to understand each other more.
Another way is to show their relationship as a power struggle. In the dark fanfiction, Sasuke could have new powers that make him a threat, and Sakura, not willing to be overshadowed, tries to gain equal or greater power. Their relationship then becomes about who is stronger and who will ultimately control the situation, all while their underlying feelings for each other still exist in a distorted way.
I've heard of a fanfic where Dark Avatar Korra is on a journey to restore balance in a world that has turned against the Avatar. It's a great read as it shows her using her unique powers in creative ways. The author really captures her new, edgier personality.
The origin of the Dark Avatar in fanfiction can also be very captivating. It could be a result of a corrupted spirit world influence, or perhaps a dark ritual gone wrong. Exploring how this new Dark Avatar came to be can add depth to the story and explain their motives and actions.
In such fanfiction, their relationship could be shown as a complex web of emotions. They might have a lot of unspoken feelings that surface in the 'dark' situations they face. For example, when they are in a dangerous battle, Sasuke might show his protective side towards Sakura in a more aggressive way than usual, which could lead to some intense moments between them. The 'lemon' aspect could add a layer of physical passion to their relationship, but it should be done in a way that still respects the characters' core personalities.
In fanfiction, their relationship might be shown as a yin - yang type of situation. Zekrom, representing electricity and Reshiram, representing fire, could be like two sides of the same coin. They might be initially distrustful, but as the story progresses, they could discover that they are both essential for the balance of the Pokémon world. This could be shown through a series of events where their actions inadvertently affect each other, and they start to understand the importance of the other's existence.
Another way is to portray it as a complex relationship filled with envy. Poseidon might envy Zeus's position as the king of the gods, while Zeus could be envious of Poseidon's power over the vast oceans. This envy could lead to various power struggles and tense moments between them in the fanfiction.
Another way is to show it as a relationship full of tension. They don't trust each other completely but they know that they need each other for certain goals. For instance, they might be collaborating on a project to spread more fear in the world, but each is secretly planning to double - cross the other when the time is right.
The relationship can also be portrayed as a mentorship of sorts. Hermes, being the younger god, could look up to Apollo in certain aspects like art and prophecy. He might ask Apollo for advice on how to create beautiful melodies (even though Hermes is more known for his flute). Apollo, in turn, could be impressed by Hermes' quick thinking and ability to get out of tight situations, and learn from him in terms of adaptability. This dynamic would add an interesting layer to their relationship in fanfiction.