Kakashi and Stein would be really interesting. Kakashi is a very experienced and intelligent ninja, while Stein is a mad scientist - type in Soul Eater. Their different approaches to combat and knowledge could lead to some fascinating exchanges. Kakashi might be intrigued by Stein's experiments on souls, and Stein could be interested in Kakashi's Sharingan and how it works in relation to the body and mind.
I think Naruto and Maka would be an interesting pairing. Naruto's energetic and determined personality combined with Maka's focus on collecting souls and her academic side would create an interesting dynamic. They could learn a lot from each other, like Naruto teaching Maka about perseverance in the face of impossible odds, and Maka showing Naruto the importance of knowledge in combat.
Another great pairing could be Sasuke and Soul. Sasuke's brooding and power - hungry nature contrasted with Soul's laid - back but also powerful self. They could have some intense battles together, and perhaps Soul could help Sasuke come to terms with his inner demons in a different way than in the Naruto universe. Also, they both have a certain 'cool' factor that would make their interactions exciting.
Ichigo and Maka would be an interesting pairing. Ichigo is a powerful Soul Reaper with a strong sense of justice, and Maka is a determined Meister. They could learn a lot from each other's fighting spirit. Another great pairing could be Soul and Rukia. Soul's laid - back yet powerful nature combined with Rukia's cool and collected demeanor would make for some interesting interactions. And also, Death the Kid and Byakuya could be an intriguing pair. The precision - loving Kid and the stoic Byakuya would have a lot of contrasts and potential for character development.
Definitely Naruto and Hulk. Just imagine Naruto trying to calm down the Hulk when he's angry. It would be hilarious. And on a more serious note, Naruto's positive energy might have an effect on the Hulk. Also, Sakura and Captain America. Sakura is a strong - willed and powerful female character, and Captain America is a symbol of leadership and justice. They could bond over their shared values and exchange fighting strategies.
Naruto and Ruby would be an interesting pairing. Naruto's positive attitude and never - give - up spirit could mesh well with Ruby's determination. They could both inspire each other in combat and in their personal growth. Another good pairing could be Sasuke and Blake. Sasuke's brooding nature and his search for power could be contrasted with Blake's own past and her fight for equality. They could have some deep conversations about their motives and past traumas.
Hawkeye and Sasuke would make a cool pairing. They are both very skilled in ranged combat. Hawkeye could learn some of Sasuke's Sharingan - enhanced archery skills, and Sasuke could be interested in Hawkeye's high - tech arrows. Also, Iron Man and Kakashi would be an interesting match. Iron Man's love for technology and Kakashi's use of Sharingan - based tech like his Ninja Hound summons could lead to some great interactions. They could even collaborate on creating new gadgets for both universes.
I think Sasuke and Tygra would make a great pairing. Sasuke has his Sharingan and his complex personality, while Tygra is a strategic thinker with his own set of skills. They could have some intense battles together against common enemies, and also have deep conversations about power and purpose. Also, Kakashi and Panthro would be cool. Kakashi's vast knowledge of ninjutsu and Panthro's mechanical expertise could lead to some interesting exchanges and combined efforts in combat.
Naruto and Luffy would be a really interesting pairing. Naruto's determination and Luffy's carefree but strong - willed nature could lead to some great interactions. They both have big dreams and are leaders in their own ways. Another interesting pair could be Sasuke and Zoro. They are both very skilled fighters with a somewhat brooding nature. They could have some intense sword - versus - sword (or sword - versus - katana) battles and also learn from each other's combat styles.
Itachi and Roy Mustang would be an interesting duo. Itachi, with his complex past and powerful abilities, and Roy Mustang, with his ambition and strategic mind. They could share their knowledge of different forms of combat and power manipulation. Itachi might be intrigued by Mustang's use of alchemy for combat, and Mustang could be interested in Itachi's Sharingan abilities and how they can be used in battle.
I think Naruto and Luffy would make an amazing pairing. Naruto's never - give - up attitude combined with Luffy's boundless enthusiasm would be really exciting. They could learn from each other, like Naruto teaching Luffy some basic ninja skills and Luffy showing Naruto how to be even more carefree and fearless.
Hawkeye and Sasuke would make an interesting pair. Hawkeye is an expert archer, and Sasuke is a skilled ninja with his own unique form of ranged attacks. They could have a friendly competition to see who has better aim. And they could also learn from each other's combat styles. Hawkeye could teach Sasuke about modern weaponry and Sasuke could show Hawkeye some of his ninja stealth techniques.
Naruto and Pikachu would be an interesting pairing. Naruto's high energy and Pikachu's feisty nature would make for some great adventures. They could both learn from each other's determination and loyalty to their friends. Another good pairing could be Sasuke and Charizard. Sasuke's brooding and powerful nature would match well with Charizard's strength and proud demeanor.