There could be a wise old sage who has foreseen the OC's rebirth as the dark avatar and decides to guide them. This sage might have knowledge of ancient prophecies that suggest the OC can use their new power for good. Also, an unexpected ally could be an enemy of a greater evil. They realize that the OC's power as the dark avatar can be used to fight against a common foe.
First, decide on the OC's origin. Are they from Earth in the Injustice universe, or from somewhere else? If they're from Earth, what kind of upbringing did they have? For example, if they grew up in a war - torn area because of Dark Superman's actions, it would shape their character. Next, think about their motivation. Is it revenge against Dark Superman, or a desire to restore true justice? Also, give them some unique traits, like a special skill or a distinct personality quirk. For instance, they could be extremely stubborn in their beliefs, which would lead them to take on Dark Superman even when others won't.
Some 'dark oc fanfiction' involves re - imagining classic fairy tales in a much darker way. The original character could be a victim of a powerful and evil force, like in a version where the OC is trapped in a cursed forest ruled by a malevolent witch. They have to fight not only for their freedom but also their very sanity.
Well, Moriarty in an 'elegant dark poise' in an OC fanfiction could be really interesting. It might show him as a very sophisticated villain. He could be portrayed with a certain grace while still being menacing. Maybe the fanfiction focuses on his inner thoughts and how he plans his devious schemes with that air of elegance.
One way to develop the OC's dark side personality is through their relationships. For example, if they had a love interest before, have them start to view that person as a weakness and cut them off coldly. They could also start to enjoy causing pain or fear in others, whether it's physical or psychological. And as they go deeper into the Sith teachings, they become more and more power - hungry, willing to do anything to gain more strength in the Force.
To create a compelling dark OC in My Hero Academia fanfiction, start with a strong motivation. It could be envy towards the heroes' popularity or a desire for power at any cost. Their quirk should be something that can cause chaos, like a mind - control quirk but with limitations such as it only works on those with weak wills. Appearance - wise, they could have a scar or some disfigurement that adds to their intimidating factor. And don't forget to give them a name that suits their dark persona.
A powerful Nightsister could be a great OC. The Nightsisters have their own connection to the dark side of the Force. An OC Nightsister could use her magic and knowledge of the dark side to interact with Anakin. She might offer him new ways to use the Force, like some of the unique spells and abilities that Nightsisters possess.
Another concept is the relationship between the 'dark doctor' and the other characters in the story. There could be a cat - and - mouse game with the authorities who are trying to stop their unethical behavior. Or perhaps there are other doctors or patients who are both afraid of and in awe of the 'dark doctor', leading to complex and dynamic interactions within the fanfiction.
First, create a really interesting original character (OC). Think about their backstory, especially elements that could lead to a dark path, like a tragic childhood or a fateful encounter. For example, if your OC witnessed the death of their family at a young age, it could be a starting point for their dark journey.