One possible plotline could be Harry's journey to become a Royal Marine, facing all the tough training. Maybe he overcomes his own fears and insecurities during the process.
Perhaps there could be a plotline where Harry uses his unique skills or knowledge from his background to solve a major problem in the Royal Marines. It could be something like using his understanding of diplomacy to handle a tricky international situation that the Marines are involved in.
One idea could be that the Royal Marines are called in to help Hogwarts during a major attack. They use their military tactics along with magic to fend off the dark forces. Maybe they train the students in some non - magical combat skills too.
One interesting plotline could be a discovery that Harry has a long - lost royal bloodline. Maybe he is related to an ancient wizarding royal family. This could lead to him having special powers or a new status in the wizarding world that challenges the existing power structures.
One interesting plotline could be the discovery of a long - lost royal bloodline among the wizarding families in the Harry Potter universe. This might lead to a power struggle as different factions vie for control or influence over this newly revealed heritage.
One possible plotline could be Harry discovering his royal heritage and how it ties into the wizarding world's history. Maybe he has a special connection to an ancient royal wizarding family that gives him new powers or responsibilities.
Some fanfictions might explore how Harry's royal heritage affects his relationships with other characters. For instance, it could create tension with the pure - blood families who see him as a threat to their own status. Or it could lead to new alliances with characters who are interested in using his royal connections for their own purposes.
Well, obviously Harry is one of the main characters. There might also be his drill instructors who play a crucial role in his training and development within the Royal Marines.
A plotline might involve Harry having to use his new - found royal fae powers to save his kingdom or the fae realm from a great danger. This could include battles against dark forces, whether they be other malevolent fae or some external threat. He may also have to navigate the complex politics of the royal fae court, dealing with rivalries and alliances.
Harry Potter himself could be one of the main characters. He could interact with the Royal Marines, learning from their discipline and sharing his magical knowledge. Another could be a tough Royal Marine sergeant who has to adapt to the magical world.
In the Napoleonic Wars, Royal Marines played a significant part. They were on ships and also participated in land battles. They were skilled in both naval combat and fighting on land. There was a story where a small group of Royal Marines held off a much larger French force for days until reinforcements arrived. Their discipline and use of the terrain to their advantage allowed them to survive and ultimately be victorious.
Some fanfictions explore a different relationship dynamic between them. Maybe Harry has a problem that only Hermione can understand and help him with, and this brings them closer in a way that's different from their normal friendship. It could be something related to his connection with Voldemort or his family history.