Develop a backstory for your OC. Maybe they were a human who was turned into a Noah under special circumstances. This backstory can explain their motives and how they view the conflict between the Exorcists and the Noahs. Also, think about their relationships with other characters. Do they have a special bond with a particular Exorcist or Noah? This will make them more believable.
First, study the existing Noahs in D Gray - Man. Notice their characteristics, powers, and personalities. Then, for your OC, give them a distinct power that still fits within the world's rules. For example, if all Noahs have some form of elemental control, your OC could have control over something like shadow or light.
One possible scenario could be that Allen is forced into a situation where he has no other choice but to become a Noah. Maybe he is tricked by a powerful Noah who manipulates his past traumas and the power of Innocence within him. The dark side of the Noah's power might seem appealing in some way, like offering him a way to end his constant struggle against the Akuma and the Earl.
One idea could be an OC who is a Noah with a unique power that allows them to manipulate time on a small scale. This could lead to interesting interactions with the main characters as they try to figure out the OC's motives and abilities.
First, you need to research the D Gray - Man Noah universe thoroughly. Know the characteristics, powers, and motives of the Noah characters. Then, when creating the abused child character, give them a believable backstory and personality. For the plot, think about how the two elements will interact. Will the Noah be the savior of the child? Or will there be a more complex relationship? You can start with a simple outline, like the introduction of the child's situation, the encounter with the Noah, and how their relationship develops over time.
First, study the characters from the D.Gray - Man series. Understand the nature of the Noah and the significance of the Mother figure. Then, come up with a unique plot. For example, you could set it in an alternate universe where their relationship is different from the canon.
Think about how your OC will interact with the existing characters. Will they form a strong bond with Allen Walker? Or have a rivalry with Kanda? These interactions can create interesting storylines. And don't forget to have a clear plot. Whether it's a mission - based story or a character - development - centered one, a well - structured plot will keep the readers engaged.
Another approach is to have a story where the abused child has a connection to the D Gray - Man Noah world without realizing it at first. For example, the child could be a descendant of someone important in the D Gray - Man lore. The Noah, sensing this connection, try to use the child for their own purposes, but as they interact more, they start to feel empathy for the child's situation and have a change of heart. This would explore themes of redemption and the power of human - Noah relationships.
One common theme is the origin of the Noah and their connection to the Mother. Many fanfictions explore how the Noah came to be and what role the Mother played in their creation. Another theme is power. The Noah Mother is often depicted as a very powerful entity, and fanfictions may explore how this power is passed down to the Noah or how it affects the world around them.
One idea could be exploring the origin of their relationship. Maybe the Noah has a unique connection to the Mother figure that predates the events of the main story. This could involve flashbacks and revelations about their past interactions.
Appearance also matters. Describe your OC's looks in a way that reflects their personality and background. If they're a Greaser - like OC, they might have a certain style of clothing like leather jackets and greased - back hair. But don't just focus on the physical; make sure their actions and words are consistent with who they are.
A believable OC should have a well - defined goal. In the context of Spider - Man Homecoming, it could be something like getting into a top science school. Their abilities should also be in line with their backstory. If they were in a car accident as a child and had to have extensive physical therapy, they could have developed enhanced reflexes from all the training. Their dialogue should also be unique. Use words and phrases that are characteristic of them. If they're a bookworm, they might use more intellectual language. And always make sure their actions are consistent with their character traits throughout the fanfiction.