Well, one possibility could be that Harry, through some sort of magical accident or powerful spell, gets transported to the world of Loki. Maybe he initially mistakes Loki for a powerful wizard and tries to seek his help to get back home. Loki, being the trickster he is, might see Harry as an interesting pawn in his schemes against the Asgardians or other foes. Harry, with his own magical skills from the wizarding world, could end up being both a hindrance and a help to Loki, leading to all sorts of adventures and misadventures as they navigate their two very different magical realms.
It could be that in the 'Harry joins Loki fanfic', the multiverse is collapsing. Harry, as a powerful wizard, and Loki, as a god with his own set of skills, are brought together by some cosmic force. They are forced to work together to save both the wizarding world and Asgard from destruction. Harry's knowledge of spells and magic theory combined with Loki's cunning and ability to manipulate situations could be a powerful combination. However, they also have to overcome their differences in ideology and power sources. Harry is used to a more structured magic system based on study and discipline, while Loki's magic is more instinctive and tied to his godly nature.
Well, perhaps Harry could discover a magical portal that leads him to the Protoss world. There, he might learn their advanced technology and unique culture. Maybe he uses his magic in combination with Protoss powers to fight off some common enemies.
One possibility is that Harry joins SHIELD after realizing the magical world can't fully contain the threats he's faced. In the fanfic, he could be a key figure in bridging the gap between the magical and non - magical worlds within SHIELD. He might introduce magic - based security measures or use his ability to detect dark magic to identify threats that normal technology can't pick up.
One possible plot for 'harry joins the military fanfic' is that Harry joins the military to find a new purpose in life. He comes from a troubled background and sees the military as a way to discipline himself. He starts in a basic training unit where he meets all kinds of different people from different walks of life. As he progresses, he discovers a hidden conspiracy within the military that threatens national security. Harry then uses his wits and new - found military skills to try and expose the conspiracy and save the day.
In the 'harry joins voldemort fanfic', it could start with Harry being captured by Voldemort. Instead of killing him immediately, Voldemort decides to brainwash him. Through a series of dark magic spells and psychological manipulation, Harry starts to see Voldemort as a mentor. As time passes, Harry becomes an integral part of Voldemort's inner circle, helping him plan attacks against the wizarding world, believing that they are actually for a greater good as Voldemort has convinced him.
The plot could involve Harry using his magic in the Stargate universe. Maybe he could use spells to help the Stargate teams in their battles against the Goa'uld. For example, a simple Stunning Spell could be very useful against the Jaffa warriors. He could also use magic to decipher some of the ancient technologies that the Stargate teams come across, since he has experience with ancient magic in his own world.
One possible plot could be that Harry is brought into the SG1 world because of a magical accident involving the Stargate. Once there, he realizes that there are dark forces at work in this universe too. He teams up with SG1 to find a way to get back home while also helping them to stop an impending invasion. Harry uses his Patronus charm to fend off some of the scarier alien creatures, and his knowledge of potions comes in handy when they need to cure a strange alien disease.
The plot might revolve around Harry's adaptation to the military lifestyle. He'd have to get used to the strict discipline, early mornings, and intense physical training. Along the way, he might discover a hidden talent for air combat strategy. And there could be a sub - plot about his relationship with his family back home who are both proud and worried about him.
Maybe Harry gets tired of the regular magical schools and discovers a hidden, more specialized fourth school. There he could meet new friends and face different kinds of magic challenges.
In a 'Harry Potter son of Loki' fanfic, the plot might revolve around Harry's struggle to balance his two identities. On one hand, he's a wizard in the magical world of Hogwarts, and on the other, he's the son of a Norse god. This internal conflict could lead to external conflicts as well. For example, some of his friends at Hogwarts might be suspicious or even afraid of his newfound heritage. Meanwhile, in the Asgardian realm, he might be seen as an outsider because he was raised in the wizarding world. He has to find a way to bridge these two worlds and prove himself worthy in both.
The plot could involve the Firebird being a long - lost magical artifact in the wizarding world. Loki, who has a knack for finding powerful and mysterious things, stumbles upon it. Harry Potter, always vigilant about protecting the wizarding world, gets wind of Loki's discovery. Harry and his friends then set out to stop Loki from misusing the Firebird's power. There could be duels, magical puzzles, and a race against time as Loki tries to harness the Firebird's power for his own ends.