The theme of sacrifice could also be present. Maybe Harry disappeared because he sacrificed himself for a greater good. And his return could be a sort of resurrection, where he has to deal with the consequences of his sacrifice and how it has affected the wizarding world.
The setting in which Harry disappears and returns also matters. If it's in the middle of Hogwarts, the school would be in chaos. Teachers would be trying to keep the students calm while secretly searching for Harry. And when he returns, the reactions of different houses - Gryffindor being relieved and proud, Slytherin perhaps being suspicious - could add more layers to the story.
Another theme is the adjustment to a new life. Harry has to get used to living with someone in a different way than he was used to before. He may have to share his space, make compromises, and this is often explored in these stories. It also shows how his friends and the wizarding community react to his new married status.
One common theme is the exploration of how their relationship affects the wizarding world. Since Harry and Hermione are both important figures, their marriage can have political and social implications. Another theme could be the reaction of their friends and family. For instance, Ron's reaction might be a central part of the story, as he has a long - standing relationship with both Harry and Hermione.
Well, it could be that Ash disappears on a dangerous quest. His friends in the harem are distraught. When he returns, he might have new powers. And then he has to deal with the changed dynamics in the harem, like some might be angry at him for leaving, while others are just overjoyed to have him back.
Well, he might disappear because of a powerful curse from an ancient enemy. Maybe he gets trapped in a different dimension. When he returns, he could have new powers or knowledge. For example, he might have learned some secret magic from the other dimension that helps him defeat a new threat in the Percy Jackson world.
Obviously, Ash would be the main character. Then there could be female characters who form his harem. Maybe some of his long - time friends like Misty and Brock could also be involved in some way, even if they are not part of the harem directly. There might also be new characters that he meets during his disappearance.
Perhaps Harry is kidnapped by a mysterious and powerful magical being. This being has the ability to make Harry disappear without a trace. His friends then embark on a dangerous quest to find him, facing many magical challenges along the way. They might have to search in hidden and dangerous parts of the wizarding world that they have never been to before.
A group of rogue demigods could be the main antagonists. They believe that Percy is too powerful and his presence is causing more problems than solutions in the demigod world. So they make him disappear. But when Percy comes back, he shows them that they were wrong and that they have been mislead by false beliefs.
Another theme is growth. Both Naruto and Hinata may have grown separately during Naruto's absence. When he returns, they have to adjust to the new versions of each other. For instance, Hinata might have become stronger in her own way, and Naruto has to recognize that.
One common theme could be redemption. Maybe Ash has to make up for something from his past. Another theme might be reunion, like reuniting with lost friends or family.