First, start with their initial meeting. It should be a bit rocky. Bankotsu is a tough character. So, the OC needs to have some sort of quality that intrigues him, like being fearless or having a unique power. Then, as they interact more, show small moments of connection. For example, the OC might share her food with Bankotsu when they are on a journey together, and he starts to see her kindness.
One idea could be that the OC is a healer who comes across Bankotsu's gang. Bankotsu is initially skeptical of her but as she heals his wounds, he starts to develop feelings. Another could be the OC is from a rival clan but falls for Bankotsu's strength and charisma, leading to a Romeo - Juliet - style relationship within the Inuyasha universe.
It could be Naraku. Even though the focus is on Kagome and child Bankotsu, Naraku is always lurking in the shadows in the Inuyasha universe. He might see Kagome's interaction with Bankotsu as a threat to his plans and try to manipulate the situation to his advantage. He could try to turn Bankotsu against Kagome or use Kagome's distraction with Bankotsu to carry out some other evil deeds.
One interesting crossover could be where Inuyasha and his gang end up in the Naruto world. They might be mistaken for strange ninjas at first. Inuyasha could get into fights with some of the stronger ninja clans because of his brash nature. Another cool one would be Naruto somehow ending up in Inuyasha's feudal Japan - like world. He would have to adapt to the different fighting styles and the presence of demons.
Bankotsu would likely become more protective. His tough - guy exterior would soften as he has someone he truly cares about and a baby to look after. He might start to think more about the future and less about his past violent ways. Kagome, on the other hand, would become more maternal. She would be more cautious and would use her nurturing side more. She might also become more assertive in protecting her family, drawing on her own inner strength that she has developed over her adventures.
Bankotsu and Kagome fanfiction is interesting because it combines two very different characters. Bankotsu is often seen as a rough and tough warrior, while Kagome is more gentle and spiritual. A fanfiction could play on this contrast, for example, having Kagome's kindness soften Bankotsu's hard edges.
One idea could be that the baby has a special power inherited from both of them. Since Kagome has spiritual powers and Bankotsu is a strong warrior, the baby might be able to sense evil spirits from afar and also have great physical strength. This could lead to many adventures where they have to protect the baby from those who would want to use its powers for their own gain.
The main character is of course Bankotsu. As for his love interest, we don't have enough information to name them specifically. But there could be other important characters around them. Maybe a mentor figure who gives advice on their relationship, or a rival who has feelings for either Bankotsu or his love interest, which adds drama and conflict to the 'bankotsu love story'.
I'm not sure specifically which 'bankotsu love story' you're referring to. It could be a story about a character named Bankotsu and his love experience. Maybe it involves his journey in finding love, facing challenges in a relationship, or some kind of unique love encounter in a particular fictional world.
One possible fanfiction could be a story where Bankotsu, the powerful demon slayer, and Kagome, the time - traveling miko, team up to fight a common enemy. They start off as reluctant allies, but as they face challenges together, they develop a mutual respect and friendship.