What are some interesting plot ideas for a Joker x Robin fanfiction?

One idea could be that the OC is a psychologist assigned to study the Joker. As she tries to understand his mind, she gets drawn into his chaotic world. Another could be the OC is a new criminal in Gotham who catches the Joker's attention and they form an unlikely alliance against other villains. Maybe the OC has a special ability like mind - reading and the Joker wants to use it for his own gain.

One idea could be a time - travel plot where Robin from the present meets a younger Lucina. They could initially be at odds due to their different understandings of the future and past events. But as they spend time together, they start to understand each other and develop feelings. Another plot could be set during a war where they have to fight side by side and rely on each other's skills. This shared experience could bring them closer. A third idea is a story where they meet in a peaceful village and help the villagers together. Through their acts of kindness, they fall in love.

One idea could be that the OC is a new villain in Gotham who catches the Joker's attention. He decides to use the OC to make Harley jealous, which then leads to a complex love - triangle - like situation full of drama and chaos.

A more complex plot could involve a time - travel element. Maybe Robin goes back in time and meets a younger Lucina, and they have to work together to change the course of events in the Fire Emblem world. This would create a lot of opportunities for character development and relationship building between them.

Maybe in the fanfiction, a smart Luffy figures out a way to read Poneglyphs with Robin's help. This new ability draws the attention of both the World Government and other pirate crews. They then have to go on a journey to protect this new - found knowledge while also using it to uncover more secrets about the Void Century.

A story about family bonds could be interesting. Since Robin is often considered Morgan's parent in the game, and Lucina has her own complex family situation. A fanfiction could explore how they form a new family unit, dealing with the challenges of protecting each other and the world around them.

A possible plot could be a story where Takemi is kidnapped by an enemy in the Metaverse. Joker, of course, goes on a mission to rescue her. Along the way, he discovers that Takemi has some hidden strengths that she has never shown before. After the rescue, their relationship changes from just acquaintance to a more intimate friendship or even something more as they realize how much they mean to each other.

A cool plot could be that there's a mysterious threat targeting all of Batman's allies. Robin and Batgirl team up to not only find out who's behind it but also to protect each other. Along the way, they share some personal stories from their pasts that bring them closer together.

Some fanfics might explore an alternate universe where their roles are different. For instance, Robin could be a powerful mage like Tharja, and they bond over their shared magical abilities. Or perhaps they are from different kingdoms originally and their relationship has to navigate the politics between the two kingdoms while also dealing with their growing feelings for each other. This can lead to a lot of complex and interesting storylines.

One idea could be that during a dangerous adventure, Zoro and Robin get separated from the crew. They have to rely on each other's skills. Zoro's combat abilities and Robin's knowledge of ancient texts help them navigate through an ancient, forgotten island filled with mysteries and traps.