The plot could also involve the OC being an ordinary person who somehow catches the Enchantress' eye. The Enchantress uses her magic to bring the OC into the DC world of heroes and villains. As she is yandere, she gets extremely possessive and tries to isolate the OC from other heroes, creating a lot of drama and conflict in the DC universe.
Maybe the OC is a scientist who discovers something that could be a threat to the Enchantress' power. Instead of eliminating the OC, her yandere side kicks in and she wants to keep the OC all to herself. She uses her magic to make the OC trust her while she tries to figure out how to deal with this potential threat in a way that keeps the OC alive and by her side.
One idea could be that the OC is a new hero in the DC universe. The yandere Enchantress becomes obsessed with the OC because of their unique powers. She starts to manipulate situations to be around the OC more, like causing villains to attack near where the OC is so she can 'help' and get closer to them.
One idea could be that the yandere female villain discovers the OC has some sort of power or knowledge that she wants for herself. So she starts to stalk the OC in the DC universe. Maybe the OC is a new hero or just an ordinary person with a connection to a powerful artifact. The yandere's actions could lead to all sorts of chaos as she tries to get closer to the OC, and the OC has to figure out how to deal with this obsessive villain while also navigating the dangerous DC world.
To write the Enchantress as a yandere, emphasize her intense emotions. For example, when she sees the OC, her eyes could glow with an unnatural light, showing her immediate fixation. Give her a possessive body language, like always standing too close to the OC or glaring at anyone who gets too friendly with them.
One plot idea could be that the OC is a new villain in Gotham. Harley Quinn becomes yandere for the OC because of their unique style of chaos. She starts to stalk the OC, leaving little gifts that are both disturbing and endearing, like a dead bird with a love note.
For Harley, her yandere trait could develop as a result of her constantly being betrayed in her past relationships. When she meets the OC, she sees them as someone she can finally have complete control over, so she becomes overprotective and possessive.
The yandere female villain can be characterized by her extreme possessiveness. In the DC context, she might be jealous of any other character who gets close to the OC. For example, if the OC is friends with Batman, she would try to sabotage that relationship. She could also have a volatile temper, going from sweet and loving towards the OC one moment to enraged and violent the next if she feels the OC is slipping away.
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.
Maybe the male OC is from another dimension and gets stranded in the Teen Titans' world. His different cultural background and knowledge from his own dimension intrigue the Titans. The harem dynamic could start with simple friendships that gradually turn into something more. Raven might be attracted to his calm and collected nature in the face of the strange new world, while Starfire could be interested in his stories of his home dimension. Beast Boy might see him as a cool new friend at first and then develop deeper feelings as they spend more time together.
One idea could be that the Enchantress uses her powers to help Naruto gain a new form. Maybe she is intrigued by his determination and decides to enhance his chakra in a unique way that gives him an appearance similar to her own magic - with glowing markings and enhanced speed. Another could be that she gets lost in the Naruto world and Naruto has to help her get back home, during which they form an unlikely bond.
One idea could be that the OC was a powerful exorcist in their past life. In this reincarnation, they start off not knowing their true potential. As the story progresses, they begin to have strange dreams and visions that are actually memories from their past life. They then meet a character from their past life who helps them unlock their powers and they join the fight against demons.
First, develop your characters well. Define the yandere's traits clearly, like their possessiveness and obsessive nature. For the oc, give them unique qualities. Then, create a plot that revolves around the yandere's fixation on the oc. Maybe start with a chance encounter that sets off the yandere's interest.