Well, Harry Potter would probably become an even more powerful wizard. Thor's combat skills and physical strength could be incorporated into Harry's magical abilities. Maybe he'd be able to cast spells while doing some of Thor's epic leaps and strikes.
The main characters are Harry Potter and Thor. But it's possible that some other important characters from both universes could play a role. In the Harry Potter universe, Dumbledore might have an opinion on Harry's new training. And in the Thor universe, Odin could be aware of Thor training an outsider like Harry. Their reactions and interactions could add more depth to the story in this fanfiction.
In this fanfiction, Harry Potter trained by Thor could lead to some interesting character development for Harry. Thor's brash and confident personality might influence Harry to be more assertive. Harry could also learn about different forms of power from Thor, not just magic. He might gain a new perspective on heroism and leadership. And who knows, maybe they would go on quests together that are completely different from what Harry has experienced in the wizarding world.
One great fic could be where Fem Harry Potter, under Narcissa's training, discovers new magical abilities. Maybe Narcissa teaches her some ancient pure - blood magic techniques that the normal Hogwarts curriculum doesn't cover. This could lead to some interesting plot twists, like Fem Harry being able to use magic in a more refined and powerful way against the Dark Lord.
You can expect a lot of character development. Fem Harry would likely become more self - assured and confident as Narcissa imparts her knowledge. For instance, Narcissa might teach her proper etiquette in the wizarding high society, which would be a new experience for Harry.
Well, it might be that Harry discovers a hidden goblin training ground. There, he learns unique magic skills not taught at Hogwarts. Maybe he's taught how to use ancient goblin-made weapons in combat, which gives him an edge in fighting dark wizards.
One possible plot could be that Thor somehow gets transported to the wizarding world. He might initially be confused by the magic there as it's different from his Asgardian powers. Harry Potter and his friends could be intrigued by Thor and his hammer. They might team up to fight a common enemy, perhaps a dark wizard who has somehow got hold of some Asgardian artifact and is misusing its power.
Well, one possibility could be that Narcissa sees potential in Fem Harry Potter and trains her in the ways of pure - blood magic and etiquette. Maybe she wants to use Harry as a pawn in the wizarding world's power games. Or it could be that Narcissa, having lost Draco in some way, sees Harry as a surrogate to redeem herself. Another idea is that she trains Harry to fight against the Dark Lord from the shadows, using skills that only the Blacks possess.
In a fanfic where Harry Potter is trained by Darth Vader, it could lead to some really interesting character development. Harry, who has always relied on his friends and the wizarding world's teachings, would be exposed to a whole new way of thinking. Darth Vader could introduce him to the concept of ruling through power. This would put Harry in a difficult position as he has to decide whether to embrace this new ideology or stay true to his roots. His magic could also take on a darker tint, perhaps his spells would have a more menacing look or effect. And he might start to question the black - and - white view of good and evil that he has held so far.