For this fanfiction idea, perhaps there was a hidden connection all along. Maybe a powerful wizard or an ancient Asgardian magic was involved in their family's past. Harry's life at Hogwarts would be very different with a sister like Jane Foster. He could learn about different dimensions and technologies from her. And Jane, on the other hand, could be exposed to the wizarding world's secrets. They could have adventures together, using both magic and science to overcome challenges.
Well, one way it could work is through some sort of multiverse concept. Maybe in a particular multiverse, the magical world of Harry Potter and the superhero world of Wonder Woman collide. Harry could have some sort of hidden connection to the Amazonian world. His magic could be related to the powers that Wonder Woman has in a different way. For example, his spell - casting could be a form of magic that was lost in the Amazonian world long ago.
Jane Foster could introduce Harry Potter to the concept of the Bifrost. She might show him how it works and how it can be used to travel between different realms. Harry, in turn, could share his knowledge of magic with her. They could then use their combined knowledge to go on an adventure, perhaps to a new and unknown realm.
A possible plot would be that Jane is researching something related to energy or space - time when she stumbles upon a magical rift. Out comes Harry. At first, they are both confused. But as they explore their family history, they find out they are siblings. Then they have to deal with the fact that there are forces in both their worlds that don't want them to be together. They would go on a journey to find out why and how they are related and also to protect their respective worlds from those who oppose their union.
One possible fanfiction could involve Jane Foster using the Bifrost to accidentally end up in the Harry Potter universe. Maybe she arrives at Hogwarts and is mistaken for a new kind of magic user. The students and professors would be intrigued by her Asgardian technology and different kind of magic. She could potentially teach them about the Nine Realms while also learning about the wizarding world's magic.
Well, if Harry Potter was Superman's brother, it would be a really wild combination. Harry has his magic from the wizarding world, and Superman has his superpowers from Krypton. Maybe Harry could use his magic to help Superman understand some things that are beyond his super - physical abilities, like the mysteries of the soul. And Superman could protect Harry in the Muggle world in a way that wizards might not be able to, like with his super - speed and strength against non - magical threats.
Harry Potter and Jane Foster themselves are great to pair. Their different backgrounds, one in magic and the other in science, can create a lot of interesting interactions. Hermione could also be paired with Jane Foster. Hermione's thirst for knowledge and love of learning could mesh well with Jane's scientific mind. They could exchange ideas about different forms of knowledge. Another good pair could be Thor (since he's related to Jane Foster) and Hagrid. They both have a big - hearted and strong - willed nature and could have some fun adventures together in a fanfic.
Well, a fanfiction could involve Jane Foster being a healer at Hogwarts. Since she has some medical knowledge from her own world, she could introduce new ways of treating magical injuries. Or, Harry Potter could be sent on a mission to Jane Foster's world and he has to adapt to the different technology and culture there while still using his magic to solve problems. Also, there could be a story where the Asgardian magic in Jane Foster's world has some sort of connection to the magic in the 'Harry Potter' universe, and they have to figure out how to use this connection to save both worlds from a great evil.
A common theme is the exploration of different power sources. Harry has magic and Jane has her scientific knowledge. Another could be culture shock, as they come from very different fictional cultures.
Yes, there are some out there. You can start by looking on popular fanfiction websites like Archive of Our Own. Just search for 'Harry Potter x Jane Foster' and you'll likely find a variety of stories with different plotlines and interpretations.
The plot could involve a mystery around their family. Maybe they are siblings but there are secrets about their parents that they need to uncover. As they dig deeper, they find out that their family has a special connection to an ancient magic. Along the way, they make new friends who help them in their quest. Harry's Gryffindor courage and Raven's unique traits could combine to make them a formidable duo in the wizarding world.