One idea could be to give the sister a unique power. For example, she could have the ability to control the elements, which would set her apart from Sesshomaru and Inuyasha. This power could also create interesting storylines as she might have to learn to control it.
Another aspect to consider is her backstory. She could have been through a traumatic event in the past that has shaped her into who she is. For instance, she might have been kidnapped by demons when she was young, which made her determined to become stronger. This would add depth to her character in the fanfiction.
For character development, you could explore her relationship with Sesshomaru. Maybe she has always been in his shadow and is trying to prove herself. She could be torn between loyalty to her brother and her own desires, like making friends with Inuyasha's group.
For character development, the OC could be an outcast in her own community. When she enters the world of Inuyasha and Koga, she finds a new sense of belonging. Koga's wolf pack could initially reject her, but through her determination and kindness, she wins them over. Inuyasha's friendship also helps her to see her own worth. As the story progresses, she becomes a strong and respected figure, not just among them but also in the wider world of demons and humans they inhabit.
You can also build a plot around her relationship with Sesshomaru. Maybe there is a rift between them that needs to be healed. She tries to do something to regain his trust or respect, but things keep going wrong. This internal family drama can be intertwined with external threats like demon battles.
In fanfiction, the baby could be the key to unlocking some long - lost secrets in the Inuyasha universe. Since Sesshomaru and Inuyasha have such complex histories and lineages, the baby might hold the answers to ancient prophecies. It could also have a special bond with the Jewel of Four Souls, perhaps having a unique way of controlling or protecting it that neither of its parents had. And of course, there would be all kinds of emotional drama as the two brothers - turned - co - parents deal with their new relationship.
Another fanfiction concept could be set in an alternate universe where they are all students in a school. Inuyasha might be the troublemaker, Kagome the studious one, and Sesshomaru the aloof and brilliant student. There could be a mystery at the school that they have to solve together, and through this, they form an unlikely friendship.
One great 'Inuyasha Sesshomaru x OC Fanfiction' is 'A Bond Beyond Time'. It has a really interesting plot where the OC is a time - traveler who gets entangled with Sesshomaru's quest. The way the author develops their relationship is quite engaging.
Characterization is key in a great Inuyasha Sesshomaru OC fanfiction. The writer needs to capture the essence of Sesshomaru and Inuyasha accurately. Sesshomaru should still be his aloof, powerful self, and Inuyasha his hot - headed but good - hearted character. The OC should interact with them in a believable way. Moreover, the writing style matters. A vivid and engaging writing style that can bring the feudal Japan setting of Inuyasha to life is a big plus. Good use of description, whether it's about the landscapes or the characters' emotions, can make the fanfiction stand out.
Start by deciding her backstory. Maybe she was separated from her brothers at a young age and grew up in a different environment. This could influence her values and beliefs. Then, think about her relationships. Does she look up to one brother more than the other? How does she interact with other characters in the Inuyasha universe? Also, give her flaws. If she's too perfect, she won't be believable. Maybe she's a bit too trusting or has a short temper when it comes to protecting her family.
One plot idea could be that their little sister has a unique power that both Inuyasha and Sesshomaru don't fully understand. This power could attract various demons who either want to use it or destroy it. Another idea is that she gets lost in a different realm and has to find her way back while learning about her own abilities and the relationship between her brothers.
Sesshomaru is an enigma. In fanfiction, his cold exterior and his pride as a full - demon are prominent. He initially sees Inuyasha as a weak half - breed, but as the story progresses, he may come to respect Inuyasha's growth. His relationship with Kagome can also be an interesting aspect. Sometimes he's indifferent to her, but other times he might be intrigued by her powers and her ability to change Inuyasha.
First, you need to understand the characters well. Sesshomaru is a complex character, so study his personality traits from the original series. For the OC, give her a distinct personality and backstory. For example, if she's a healer, explain how she got those skills.