A common theme could be the witch OC's struggle to fit into the 'Yuyu Hakusho' world. Since it's a different kind of character in that universe.
Another common theme could be relationships. The witch OC might form friendships, rivalries or romances with the original characters from 'Yuyu Hakusho'. This can lead to stories about loyalty, betrayal, and personal growth as they navigate these relationships within the context of the 'Yuyu Hakusho' universe.
I'm not sure of specific 'yuyu hakusho witch oc fanfic' off the top of my head. But you can start by looking on fanfiction websites like Archive of Our Own. There are often a lot of fan - made stories for 'Yuyu Hakusho' and you might find some that involve witch OCs.
Another theme is often the outsider status. Since the character is an original creation (OC), they are likely to be an outsider in the established 'Yu Yu Hakusho' world. This can lead to themes of acceptance or rejection. They may struggle to fit in among the demons, spirit detectives, and other beings in the story. Also, there can be themes related to the witch's origin. Maybe they come from a different dimension or a hidden coven within the 'Yu Yu Hakusho' world, and exploring this origin can be a major part of the story.
To develop their relationship, start with small interactions. For example, the OC could accidentally bump into Kurama in the school hallway. Kurama, being yandere, is immediately intrigued. Then, gradually build up the intensity. Maybe the OC asks Kurama for help with homework, and he uses this as an opportunity to get closer to her. He could also share some of his secrets from the demon world, which makes the OC trust him more.
One plot idea could be that the OC is a new student at Yuyu Hakusho's school. Kurama, being yandere, becomes instantly obsessed with her. He starts leaving her little gifts, like rare flowers from the demon world. Another idea is that the OC has some special power that Kurama wants to protect at all costs, even if it means getting rid of anyone who gets too close to her. Maybe the OC is initially unaware of Kurama's true nature and thinks he's just a friendly classmate.
One common theme is the clash of different power systems. In Naruto, there are ninjas with their jutsus, in Ranma 1/2, there's the martial arts and the curse, and in YuYu Hakusho, there are spirit powers. Writers often explore how these powers interact when the characters meet. Another theme could be the cultural differences. Naruto has its own ninja culture, Ranma 1/2 has a more comical Japanese setting, and YuYu Hakusho has a darker, more supernatural world. Seeing how characters adapt to these different cultures is also a common aspect.
Well, you can try looking on fanfiction.net. There are often a lot of 'yu yu hakusho' fanfics there. Some might feature witch OCs. You can search for relevant tags like 'Yu Yu Hakusho' and 'witch OC' to narrow down the results.
One prevalent theme is redemption. Many OCs have a past they are trying to atone for. This ties in with the moral grayness of the 'The Last Witch Hunter' world. Also, the theme of discovery is big. OCs are constantly discovering new things about the world, the magic, and the other characters. It makes for an exciting read as they navigate this unknown territory.
One common theme is the struggle for power. Witch OCs often have to deal with their own powers and how they compare to other powerful entities in the Soul Eater world. Another theme is identity. Since they are original characters, a lot of fanfics explore who they are, where they come from, and what their purpose is. And of course, there's the theme of good vs. evil. Some witch OCs might be on the side of good, trying to fight against the real evil in the Soul Eater universe, while others might be more morally ambiguous.
In Vampire Diaries OC Witch fanfiction, a frequently seen theme is the search for family. Since many OC witches are new to Mystic Falls, they look for a sense of belonging, which could be with other witches or with a group of friends they make. Another theme is the battle between good and evil. The OC witches are often in the middle of this, having to decide which side to take. Also, the theme of self - discovery is common. They learn about their powers, their past, and their place in the world as they go through different adventures.
One common theme is the male OC's journey at the witch school. This could involve making friends, facing challenges in magic classes, and dealing with rivalries. For example, he might struggle to master a difficult spell while also trying to fit in with the other students.