One idea could be that Edward embarks on a journey across different kingdoms to find a suitable partner to have an heir. He might encounter various challenges and meet interesting characters along the way.
Maybe Edward discovers a long - lost relative who has a unique ability that could help in producing an heir. This could lead to a whole series of events where he has to protect this relative while also trying to figure out how to use their ability for his purpose. In the fanfiction, there could be a lot of political intrigue and power struggles as other factions try to either help or hinder Edward's quest.
One idea could be that the heir has a unique power that no one in the Naruto world has seen before. Maybe a power that combines different elements in an unexpected way, like water and lightning to create a new type of jutsu. This would make the heir a target for those who want to use this power for their own gain.
An enchantress could also be a love interest. She might offer Edward a solution to his heir problem through magic, but in return, she wants something from him. Their relationship could be a complex one of power, love, and mystery. Edward would have to navigate through her world of magic while also dealing with his own desires for an heir and the future of his kingdom.
Another plot could involve Edward making new friends in the town. These friends could be outcasts like him, and together they form a sort of club. They could then work on projects to beautify the outskirts of the town that have been neglected.
One common plot idea is exploring his past more in - depth, like his time at the military academy. It could show his relationships with other students and how he developed his skills and personality.
One idea could be exploring Edward Mordrake's backstory more in - depth. Maybe his life before the whole 'two - faced' situation, his family, and what led him to become the tragic figure he is. Another could be a modern - day encounter with someone who has a special ability to communicate with him.
One idea could be that Edward, as a cop, is assigned to protect a key witness. During this time, he discovers a complex web of secrets and has to fight against both the criminals who want to silence the witness and some corrupt colleagues. Another plot could be Edward investigating a series of mysterious murders in the city where all the evidence points to a supernatural force. He has to overcome his disbelief in the supernatural to solve the case. And also, Edward could be a rookie cop who gets involved in a big drug - bust operation and has to prove himself to his more experienced partners.
One idea could be that Harry and Edward meet in a magical forest that exists between the wizarding world and the vampire realm. They initially mistrust each other but then find out they have a common enemy and have to team up to defeat it.
One idea could be that the heir, as Naruto's descendant perhaps, has to navigate the complex relationships within the harem. Each member of the harem could represent a different clan or group, and he has to balance their interests while also dealing with his own growth as a ninja.
One idea could be that they go to a secluded beach and discover a hidden cove with magical properties. Another could be a trip to a foreign city where they encounter a vampire from an ancient lineage. And they might also go on a mountain vacation and face some dangerous supernatural creatures there.
Perhaps in the fanfiction, there is a parallel universe where Kim and Edward are from different social classes in a more modern - day setting. Kim is a famous artist who is intrigued by Edward's unique sculptures made with his scissor hands. They start to collaborate on art projects, and gradually fall in love as they break down the barriers between their different worlds.