I think Makoto Niijima from Persona 5 and Rin Tohsaka from Fate Stay Night would be a great pairing. Makoto is a strong - willed student council president, and Rin is a powerful mage. Their meeting could result in some intense discussions about leadership, power, and the use of their respective abilities. Plus, they both have a no - nonsense attitude which could lead to some interesting clashes and cooperation.
Rin Tohsaka from Fate Stay Night and Astolfo from Fate Apocrypha. Rin is a serious and intelligent mage, while Astolfo is a carefree and somewhat eccentric Servant. The combination of Rin's no - nonsense attitude and Astolfo's wacky behavior would make for some really interesting and humorous exchanges.
One interesting concept could be the fusion of the Persona summoning system with the Servant system in Fate Stay Night. Imagine a character being able to summon both a Persona and a Servant, and how that would change the power dynamics and strategies in battles.
Another great combination could be Archer from Fate Stay Night and Kazuya from Freezing. Archer's cynical and experienced nature would contrast well with Kazuya's more naive and kind - hearted personality. In a battle situation, Archer's long - range archery skills combined with Kazuya's support abilities for the Pandora could create some really cool combat scenes. Plus, their different outlooks on life would lead to some interesting philosophical discussions between them.
Saber would be really interesting. Her noble and chivalrous nature would contrast with the rough - and - tumble world of Skyrim. She has a strong sense of justice and honor, which could put her at odds with some of the more morally gray characters in Skyrim. Her swordsmanship skills would be a great asset in a land full of combat, and her magical abilities could be a mystery to the mages of Skyrim. Also, her backstory as a king in her own world could lead to some really interesting interactions with the Jarls and other leaders in Skyrim.
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.
Solaire from Dark Souls and the Hunter from Bloodborne could make an interesting pair. Solaire is known for his sunny disposition and quest for his own sun, while the Hunter is all about the hunt in the dark and gothic world of Bloodborne. Their different outlooks and skills could lead to some great character development as they face challenges together.
It's really hard to say who would be the most powerful. On one hand, in Fate Stay Night, Servants like Gilgamesh have incredible power. His Gate of Babylon contains countless noble phantasms. But in the Naruto world, characters like Naruto in his Six Paths Sage Mode are also extremely powerful. He has the power of the tailed beasts and can use all kinds of powerful jutsu. However, if we consider a crossover, it might be someone who can combine the powers from both worlds. For example, if a mage from Fate could learn to use chakra and combine it with their magic, they could be very powerful. Or if Naruto could somehow gain the abilities of a Servant, like the ability to use noble phantasms, he would be unstoppable.
I think Archer from 'Stay Night' and Jeanne from 'Apocrypha' would be an interesting pairing. Archer is a complex character with his own set of ideals and a tragic past. Jeanne, being a Saint, has a very different set of values. Their interactions could be full of philosophical debates as well as strategic planning when facing a common enemy. Another interesting pairing could be Rin from 'Stay Night' and Sieg from 'Apocrypha'. Rin is a powerful mage and Sieg is a unique Servant. They could learn a lot from each other's magic and abilities.
The interaction between Yu Narukami from Persona 4 and Makoto Yuki from Persona 3 could be really interesting. Yu is a very calm and perceptive leader, while Makoto has his own sense of leadership. They could share their experiences in leading their respective teams and learn from each other.
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.