One idea could be that the reincarnated character uses their modern knowledge to improve Damian's combat skills in a new and unexpected way. For example, introducing new training methods from different martial arts styles around the world.
Another plot could be that the reincarnated Damian has a different personality due to the new soul. He could start to question some of the more violent teachings he has received and tries to find a more peaceful way to fight crime, which causes a rift and then a new understanding within the Bat - family.
Maybe the character reincarnated as Damian remembers a future event related to the Bat - family and tries to prevent it. This could lead to some really interesting interactions with Bruce Wayne and the other members as they initially don't believe him.
Perhaps a story where Damian gets kidnapped by an old enemy of Batman. Batman then has to race against time to save him, all the while reflecting on their complex father - son relationship. This could involve flashbacks to how Damian came into Batman's life and how they've grown together.
The OC could be a scientist who is working on a top - secret project that has implications for Gotham's safety. Damian gets involved when he realizes there are bad guys after the OC and the project. As they work together to protect the project and each other, a romantic relationship blossoms. Their relationship is also tested by Damian's strict code of justice and the OC's scientific ethics.
One idea could be Damian having to face a new super - villain who specifically targets him because he's the new Batman. This villain could be someone with a personal vendetta against the Wayne family. Another plot could involve Damian struggling to live up to the legacy of Bruce Wayne as Batman while also trying to put his own spin on the role. Maybe he starts to use some of his more extreme combat training techniques that Bruce was hesitant to use.
Well, perhaps there's a plot where Raven is injured during a battle. Damian, who has always been stoic, is overcome with worry for her. He stays by her side as she recovers, and during this time, they have deep conversations about their lives, fears, and hopes. This emotional connection builds up to a kiss. Or it could be a story where they are forced to pretend to be a couple for a mission. At first, it's all just an act, but as they play their parts, they start to feel real emotions and end up sharing a kiss.
Maybe they discover they are brothers through some supernatural or scientific means. At first, they don't get along as they have very different personalities. Danny is more laid - back while Damian is intense. But as they face challenges together, they learn to trust and rely on each other.
A possible plot could be that Damian Wayne, while on a solo patrol, stumbles upon a Young Justice operation gone wrong. He steps in to help but is critical of their mistakes. This starts a tense relationship. As the story progresses, they are forced to work together on a larger threat that endangers not only Gotham but also the world. Along the way, Damian starts to understand the importance of friendship and trust within a team, which is something he hasn't really experienced before. And the Young Justice team also learns to see past Damian's prickly exterior and appreciate his skills and determination.
One interesting scenario could be Thomas Wayne seeing Damian's combat skills and being both proud and a bit shocked. After all, Thomas may not have expected such a young and fierce fighter in the family. Another could be them having a deep conversation about family values, with Damian learning from Thomas about the Wayne legacy from its very origin.
One possible plot idea could be the two of them dealing with the initial shock of the pregnancy. They might struggle with how to tell their families and friends. Another could be them preparing for the baby, like setting up a nursery in the Batcave or Raven's mystical realm. They could also face challenges from villains who see the unborn child as a potential threat or a tool for their evil plans.
You can focus on Damian's relationships in a new light. For instance, explore his relationship with his mother Talia al Ghul from the perspective of someone reincarnated. They might have different interactions as the reincarnated character has different values and experiences.
Perhaps the reincarnated character has a special ability that allows them to communicate with the unique monsters in the Tensura world. This ability could lead to forming alliances that no one else could, and they could use these to their advantage to gain power and protect the world from new threats.