One plot idea could be that Raven and her sister have to team up against a powerful dark force that threatens their world. They start off with a rocky relationship due to past differences but as they fight together, they begin to understand and respect each other more. Another idea is that Raven's sister gets possessed by an evil entity and Raven has to find a way to save her without harming her. It could involve Raven delving deep into her own powers and emotions to find a solution.
One plot idea could be that Raven's sister comes to visit and initially causes chaos among the Teen Titans. But as the story progresses, she and Raven work together to defeat a powerful enemy that was targeting both of them. This would show their growth as sisters and how they can be a powerful team.
A possible plot is that Raven senses an otherworldly power, which turns out to be Naruto. As they meet, they realize they have a connection through their complex pasts. They could go on a journey to discover the origin of this connection. Along the way, the Teen Titans are initially suspicious of Naruto but as they see his skills and his good heart, they accept him. Naruto and Raven might develop a romantic relationship as they bond over their shared experiences of being different from others in their respective worlds.
One plot idea could be Raven and Terra teaming up to face a new, powerful enemy that neither could defeat alone. They start off distrusting each other but as they battle, they learn to rely on one another's powers. Another idea is a story set in an alternate universe where Raven and Terra are from different factions but fall in love, causing them to question their loyalties. A third could be that Terra has lost her memory and Raven is the only one who can help her regain it, leading to a deep emotional bond between them.
One idea could be Raven struggling with her powers in a new way. Maybe there's a spell that backfires and gives her a strange new ability that she has to learn to control. This could lead to some comical situations as well as some self - discovery for her character.
The female OC could be a healer. Raven often gets injured during battles, and the OC uses her healing powers on Raven. This creates a connection between them. Eventually, they start to explore each other's pasts and find that they have more in common than they thought.
Their relationship can be developed through shared experiences. For example, they could go on a mission together where they face a difficult enemy. By relying on each other during the fight, they start to see each other in a new light. Another way is through communication. If they have an honest conversation about their feelings, past misunderstandings can be cleared up, which helps to strengthen their bond.
Their relationship could be developed uniquely by having them swap powers for a short time. This would force them to understand each other on a deeper level as they experience what it's like to have the other's abilities. It could lead to some humorous and also some very poignant moments between them.
One idea could be that the OC demon is on a mission to steal a powerful artifact from Raven, but as they interact, they start to develop an unexpected friendship that turns into more. Another could be that the OC is an outcast in the demon world and Raven, with her own struggles of being different, helps the OC find her place. Maybe they have to team up to fight a common enemy that threatens both the human and demon realms.
Maybe there's a device that mixes the powers of Pokemon and the abilities of the Teen Titans. Ash and Raven find this device and have to figure out how to control it before it falls into the wrong hands. Along the way, they learn about each other's worlds and grow as characters. Ash could teach Raven about the bond between a trainer and Pokemon, and Raven could show Ash some new ways to use his strategic thinking with her knowledge of magic and combat.
One possible interesting plot could be Naruto and Raven teaming up to face a powerful common enemy. Their different powers from their respective universes, Naruto's ninja skills and Raven's magic, would make for an exciting combination in battle.