Honestly, it might be a combination of characters. For instance, if Batman and Hermione Granger worked together. Batman is known for his intelligence and strategic planning. Hermione is extremely intelligent and well - versed in magic. Batman could come up with a plan to take on a powerful enemy, and Hermione could use her magic to execute it. They could analyze the enemy's weaknesses, whether it's a superpower or a type of magic, and then use their combined skills to defeat them. This combination of brains and magic could make them a very powerful force in the combined fanfiction world.
Sasuke could also be a very powerful character in this crossover. His Sharingan abilities combined with some of the dark magic from the Harry Potter world could make him a formidable opponent. But then again, Hermione with her quick thinking and ability to master new spells could also hold her own against him. It really depends on how the crossover is set up and what abilities are allowed to be combined.
It could be Akuma. He is extremely powerful in the Street Fighter universe with his dark Hadou powers. In a combined universe, his ability to manipulate dark energy could be enhanced by the magic in the Harry Potter world. He could potentially learn spells and use them in combination with his fighting skills, making him an almost unstoppable force.
I think Harry Potter himself would be very powerful in this crossover. He has the experience of fighting dark wizards and his magic skills. If he was in the MHA world, he could use his magic to enhance his physical abilities like the characters with quirks. His ability to resist the Imperius Curse and his knowledge of defensive magic would give him an edge over many MHA villains.
It's really hard to say. Naruto with his godlike powers would be extremely powerful. He can do things like create massive Rasengans and has near - unlimited chakra. But Superman in the Justice League also has incredible strength, speed, and heat vision. He can fly at supersonic speeds and is nearly invulnerable. However, if Naruto's godlike form gives him the ability to manipulate time and space like some of the Otsutsuki in his world, he might have an edge over Superman.
It's hard to say for sure, but Superman could be a top contender. His super strength, speed, and flight, along with his heat vision and other abilities, make him extremely powerful. He can withstand a lot of damage and dish it out just as well.
It could be Albus Dumbledore. He has great magical knowledge and power in the 'Harry Potter' universe. When combined with the 'Fate Stay Night' elements, he might be able to outwit even the most powerful Servants. His ability to plan and his understanding of magic could give him an edge in any conflict.
Well, if we consider Harry Potter himself, he has the power of love and the ability to face great evil. But when compared to some of the Servants in 'Fate Stay Night', he might seem less powerful at first glance. But his determination and the fact that he has overcome death multiple times could give him an advantage. On the other hand, a character like Archer from 'Fate Stay Night' has a wide range of skills and the ability to analyze situations quickly. In a combined fanfiction, it would depend a lot on the situation and how the powers interact. For example, if it's a battle of wits, Dumbledore or Archer might have the upper hand, but if it's a battle of pure power, Gilgamesh or a magically enhanced Harry Potter could be the victor.
Definitely Harry Potter and Batman. Harry has his own set of skills dealing with magic and the dark arts, while Batman is a master strategist and detective. They could learn a lot from each other. Batman could teach Harry about non - magical combat and investigation techniques, and Harry could introduce Batman to the world of magic.
Wonder Woman and Ron Weasley could be an interesting combination. Ron is often underestimated but has a lot of heart and loyalty. Wonder Woman, with her strength and noble character, could inspire Ron to be more confident in himself. Ron could introduce Wonder Woman to the fun and sometimes chaotic side of the wizarding world. They could work together to fight off enemies, with Ron using his magical skills and Wonder Woman using her combat and leadership skills.
In my opinion, it could be Scarlet Witch. Her reality - warping powers are extremely potent. In a crossover, she could potentially change the very fabric of the combined universes. If she were to go rogue or be influenced by an evil force, she could cause chaos on a scale that would be very difficult for the combined might of the Justice League and the Avengers to handle. Even Superman's invulnerability might not protect him from her reality - warping abilities. She could simply make him mortal or take away his powers altogether.