Who would be the most interesting character pairings in a 'Fate Blue Exorcist Crossover Fanfiction'?

Weiss and Rin could be a great pair. Both are strong - willed and come from families with a certain reputation. Weiss's elegance in combat with her Glyphs and swordsmanship could be complemented by Rin's powerful magic. They might start off as rivals, constantly trying to one - up each other, but eventually realize they can achieve more by working together.

Castiel and Frank Reagan could also be an interesting pairing. Castiel with his angelic powers and Frank with his leadership and experience in the police force. Castiel might not understand all of the human politics and procedures that Frank deals with, and Frank might be initially shocked by Castiel's otherworldly nature, but they could find common ground in protecting the city from a major supernatural disaster.

I think a pairing between Shiba Tatsuya from Mahouka and Archer from Fate would be really interesting. Tatsuya is a very powerful and intelligent magician in his own right, and Archer has a wealth of combat experience and a complex personality. They could have some great philosophical debates about the nature of magic and the purpose of their powers.

One of the most interesting pairings would be Saber and Elsa. They are both strong female characters with powerful magic. Saber could teach Elsa about combat and leadership, while Elsa could show Saber how to better control her magic in a more natural way. Also, Kristoff and Lancer could be an unexpected but interesting pairing. Lancer's pride and Kristoff's down - to - earth nature would create some fun interactions.

I think Tucker from Red vs Blue and Yang from RWBY would be an interesting pairing. Tucker is known for his laid - back but confident attitude, and Yang is a strong and fearless fighter. They could bond over their combat skills and exchange stories about their respective worlds.

Yukari (from Persona 3) and Chie (from Persona 4). Yukari is very outspoken and has a bit of a sarcastic side, while Chie is energetic and a bit of a tomboy. Their different personalities could lead to some really fun and comical interactions, especially when they're facing Shadows together or just hanging out in the school setting.

Luke Skywalker and Caster could be an exciting pairing. Luke's journey from a simple farm boy to a powerful Jedi could be paralleled with Caster's often complex and magical nature. Caster could potentially teach Luke some new ways of using the Force that are more magically inclined, while Luke could show Caster the power of hope and redemption that is so central to the Star Wars saga.

I think Kakashi and Riddick would make an interesting pair. Kakashi is a highly skilled ninja with a lot of wisdom, and Riddick has his own set of skills and street - smart knowledge. They could exchange ideas about combat strategies. Also, Hinata and Riddick could be an unexpected but interesting pairing. Hinata's gentle and shy nature could be a foil to Riddick's rough exterior, and she might be able to show him a different way of looking at things in the Naruto world.