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.
Incorporate some mystery into the plot. For example, the sister discovers an ancient prophecy that seems to be related to her. She has to figure out what it means and how it will affect her future. This mystery can drive the story forward as she uncovers clues and makes new allies and enemies.
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.
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.
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.
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.
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.
You can start by looking on fanfiction websites like Archive of Our Own (AO3) or FanFiction.net. AO3 often has a great variety of Inuyasha Sesshomaru OC fanfictions with different themes and writing styles. FanFiction.net also has a large collection, though the quality may vary more. Another option is to join Inuyasha - related forums or groups on social media platforms, where fans might share their favorite OC fanfictions or even write their own and post links there.
Sesshomaru would be very much in control of his emotions on the surface. But deep down, he'd be worried about how this would affect his status among the demons. He might start to question his own identity and what it means to be a demon in this new situation. His reaction would be slow - evolving as he tries to understand the implications. Inuyasha would initially be in disbelief, but as he starts to feel the baby move or experience other symptoms, he'd have a complete change of heart. He'd become more responsible and start thinking about how to provide a better future for the child. He might also have to deal with his own insecurities about being a good father, given his own troubled past.
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.
Sesshomaru would raise the baby with a combination of discipline and protection. He would protect the baby from any threats, using his powerful abilities. At the same time, he would discipline the baby when it made mistakes, teaching it the ways of the demon world. Inuyasha, on the other hand, would add a more carefree and emotional touch to the parenting, creating a balance in the baby's upbringing.
A popular one is 'The Meeting of Paths'. This fanfiction focuses on a situation where Inuyasha and Sesshomaru meet under different circumstances than in the original series. It has great characterizations, and the way the two interact and gradually change their views of each other is really well - written.