Well, often there's the theme of self - discovery. As they become mates, both Sesshomaru and Kagome learn more about themselves. And also, the theme of loyalty. They have to show loyalty to each other in the face of challenges from their respective worlds, whether it's the demon world for Sesshomaru or Kagome's human world. There are also themes related to power, like how their combined powers might be used for good or how they might grow in power together.
One common theme is the overcoming of differences. Sesshomaru is a demon and Kagome is a human, so there's often a story about how they bridge that gap. Another theme can be the protection aspect, with Sesshomaru protecting Kagome from various threats.
In many of these fanfictions, a common theme is the exploration of their feelings. At first, they might be at odds or not understand their feelings for each other. But as the story progresses, they start to realize their love and attraction. Another theme is the acceptance within their communities. Since their relationship is a bit unconventional, they have to deal with how their friends, family, or fellow demons/humans accept their mating.
Love against all odds is also a frequent theme. Given their initial enmity or indifference towards each other, seeing them fall in love and become mates is a central aspect. Their relationship often has to overcome obstacles like other suitors, family expectations (in sesshomaru's case, perhaps his clan's view), and their own personal biases.
The theme of redemption can be found in many 'sesshomaru x kagome mate fanfiction'. Sesshomaru may have a dark past or actions that he needs to atone for, and Kagome's love and influence help him on that path. Another theme is the exploration of new powers. Their union may unlock new abilities for either or both of them. And of course, the theme of acceptance, as they have to accept each other completely, flaws and all, in order to have a successful relationship.
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.
One common theme is the power dynamic between Sesshomaru and Kagome. Sesshomaru is a powerful demon and Kagome has her own unique powers as the reincarnation of Kikyo. Their relationship often explores how these powers interact.
The theme of transformation is quite common. Kagome might experience some sort of transformation, either physically or mentally, due to her association with sesshomaru, the vampire. Also, the idea of redemption can be found. Sesshomaru, who may be seen as a 'dark' character as a vampire, could find redemption through his relationship with kagome. And of course, there's always the theme of adventure as they navigate the vampire - filled world together.
One common theme is the idea of overcoming differences. Sesshomaru is a demon and Kagome is a human with spiritual powers. Their different natures often create conflict at first but then they learn to accept and even rely on each other. Another theme is growth. Both characters usually grow as individuals throughout the story, influenced by their interactions with each other.
Common themes include the power dynamic between them. Sesshomaru is a powerful demon and Kagome has her own spiritual powers, so how they interact in terms of power is often explored. Friendship is also a theme that can develop into something more. As they face various challenges in the Inuyasha universe, they start to rely on each other, which can lead to deeper emotional connections. And sometimes, there's a theme of redemption for Sesshomaru, with Kagome being a part of that journey.
One common theme is the bridging of two different worlds. Sesshomaru from the demon world and Kagome from the modern world. Another theme is the acceptance of each other's differences. Since Sesshomaru is a powerful demon and Kagome is a human with spiritual powers.
One common theme is the forbidden love aspect. Since they are from different species and often on different sides in the original story, the idea of them overcoming these barriers is popular. Another theme is redemption. Sesshomaru may find redemption through his love for Kagome.
One common theme is the growth of their relationship. Starting from distrust or indifference, they gradually come to understand and care for each other. Another theme could be adventure. They might go on quests together, facing various demons and challenges, which brings them closer. Also, the theme of cultural clash might be present, as kagome is from a different time and has different values compared to sesshomaru.