A possible plot is that they both get caught in a time - travel incident. They end up in a strange era where they are the only ones who can understand each other. They must rely on each other to survive in this new world. They face challenges like finding food, shelter, and dealing with the local inhabitants who are hostile to them. This plot would focus on their survival skills and how they adapt to the situation together without any romantic elements.
Another plot could be that Kagome gets lost in a dangerous part of the spirit world and Sesshomaru, who happens to be there, reluctantly decides to help her find her way back. As they journey through the spirit world, they encounter various challenges that force them to rely on each other. Kagome might use her spiritual powers in new ways, and Sesshomaru could show a more protective side.
One idea could be a story where Kagome and Sesshomaru have to work together to save a forest that is being corrupted by dark magic. They start off as reluctant allies but gradually come to respect each other's powers and skills.
One popular theme is the idea of redemption. Sesshomaru, who is often seen as a cold and aloof character in the original, might be on a path of redemption in fanfiction, and Kagome could play a part in that. Another theme is the exploration of power dynamics. Inuyasha's half - demon status and Sesshomaru's full - demon power, along with Kagome's spiritual powers, create an interesting mix for writers to play with.
One idea could be that their relationship starts as an unexpected alliance against a common enemy. As they spend more time together, they gradually develop feelings. When Kagome discovers she's pregnant, it could bring a new level of complexity to their relationship. Sesshomaru, being a proud demon, might initially struggle with the idea of impending fatherhood but then grow into a protective and loving partner.
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.
In a high school fanfiction, they could be part of a secret club. Kagome joins thinking it's an ordinary club, but it turns out to be a club for those with special abilities, and Sesshomaru is one of the leaders. As they train together in the club, they develop feelings for each other. Also, a plot could be that they are paired for a school dance competition and through the practices, their relationship blossoms.
One idea could be that the baby has some unique powers that are a combination of Kagome's spiritual powers and Sesshomaru's demon abilities. This could lead to various adventures as they try to protect the baby from those who might want to use its powers for evil.
One idea could be that they are forced to dance together at a supernatural ball. Their initial reluctance turns into a sort of understanding as they move in sync. Another could be a dance that is part of a magical ritual to save their world. They have to combine their powers through the dance, which leads to a new level of respect between them.
The adventure - based theme is also common. They could embark on a journey together to discover a lost land or a powerful artifact. Along the way, they face various challenges that test their skills and strengthen their relationship in different ways, like learning to trust each other more.
One idea could be that Kagome brings chocolate from her time as a gift for Sesshomaru. He is initially suspicious but then becomes intrigued by the unique taste. Another could be a story where chocolate has some sort of magical property in their world, and Sesshomaru and Kagome have to work together to control its power while also dealing with their growing feelings for each other.