Rin and Snape would also make an interesting pair. Snape is this brooding and complex character. Rin might initially be put off by his cold exterior but as she gets to know him, she could understand his pain and the reasons behind his actions. And Snape would be curious about Rin's magic which is so different from what he's used to. They could have some tense but also very thought - provoking exchanges.
Well, one possibility could be that Rin, with her magical abilities from the Fate series, enters the Harry Potter universe. Maybe she gets sorted into a Hogwarts house, perhaps Gryffindor due to her courage. She could then team up with Harry and his friends to fight against a new dark threat that combines the magic of both universes. For example, a villain who has found a way to use the Grail's power along with dark magic from the Harry Potter world.
It would probably be Harry Potter himself. He's from a world full of magic and mystery, and seeing him interact with the very real and regal world of the Queen would be fascinating.
Hermione Granger and Weiss Schnee could be a great pair. Hermione is highly intelligent and studious, while Weiss is refined and also has a great deal of knowledge. They could bond over their love for learning and perhaps work together on some sort of magical - mechanical hybrid project. For example, combining Hermione's magic knowledge with Weiss' understanding of Dust to create something entirely new.
Definitely Harry and Gaster. Harry is used to the magic in his world, while Gaster has his own set of abilities. Their meeting would be full of confusion, curiosity, and perhaps a bit of wariness. Another interesting interaction could be between Hermione and Gaster. Hermione would be eager to learn about Gaster's knowledge and would probably bombard him with questions.
I think Jack Frost would be the most interesting. He comes from a completely different world of ice and cold, and his powers are so different from the magic in the wizarding world. His carefree and mischievous nature would contrast well with the more rule - bound wizarding students at Hogwarts.
Hermione Granger and Sherlock would be an interesting pair. Hermione is extremely intelligent and well - read in magic. Sherlock is a master of deduction. She could introduce him to the complex world of magic, and he could help her with his logical thinking when it comes to non - magical mysteries at Hogwarts. They could also have some really interesting debates about the nature of knowledge, whether it's through magic or pure logic.
Hermione and Sakura would be a great combination. Hermione is highly intelligent and book - smart, while Sakura is a skilled medical ninja with her own growth arc in terms of strength and confidence. They could exchange knowledge, with Hermione teaching Sakura about the complex magic theories and Sakura showing Hermione some of the medical ninjutsu. They could also work together to solve problems, using their combined wits and skills.
I think Hermione would be really interesting too. She is so intelligent and knowledgeable about magic. When she meets Captain America, she would probably be very curious about his world and how things work without magic. She could be the one to try and find a way to bridge the gap between the two worlds, like trying to figure out how Muggle technology and magic could work together.
The interaction between Hermione and Carlisle would be really interesting. Hermione is super intelligent and always eager to learn, and Carlisle is a very old and knowledgeable vampire. They could have deep discussions about the nature of life, death, and immortality. Hermione might be fascinated by how Carlisle has managed to retain his humanity over the centuries, while Carlisle could be intrigued by Hermione's vast knowledge of magic and her strong moral compass.
I think Kakashi's interaction with Minato would be very interesting. Kakashi was Minato's student. Meeting his sensei again, especially with Team 7 in tow, would bring back a lot of memories. Kakashi could show Minato how he has grown and passed on Minato's teachings. And Minato could give Kakashi some new insights based on his own experiences.