Personally, I find Kakashi as a wolf to be the most interesting in a fanfic context. Wolves are known for their intelligence and their pack - oriented nature. Kakashi is a very intelligent character, and seeing him lead a 'wolf pack' of his comrades would be really cool. He could use his wolf - like instincts to strategize and protect his pack, just as he does with his friends in the Naruto series.
Naruto and Kenichi himself would be really interesting. Kenichi could be in awe of Naruto's power and his never - give - up attitude. Naruto could see Kenichi's determination to improve in martial arts and be reminded of his own journey to become a great ninja. They could train together, with Naruto teaching Kenichi some basic ninja moves like how to throw shuriken accurately, and Kenichi teaching Naruto some martial arts stances.
Iruka sensei could be a great character. He could use coffee as a way to bond with Naruto and the other students. In the fanfic, he could introduce them to different types of coffee from around the world (in the Naruto universe), and through these coffee - related lessons, teach them important life lessons as well.
I think Rock Lee would be really interesting. His extreme dedication to training and his unique fighting style would be a great contrast to the often chaotic and self - serving characters in the GTA world. He could run around the GTA streets, challenging the thugs to combat and trying to uphold his ninja code in a very different and morally ambiguous environment.
I think Kakashi would be a great choice. He's already a very versatile character. If he had Frozone's ice powers, he could combine it with his Lightning Blade technique. He could freeze enemies in place and then finish them off with his lightning - enhanced sword. His intelligence would also make him very creative in using these new powers.
Naruto himself would be the most interesting. Just imagine him, with his energetic and determined personality, now having this strange connection to the song. His singing would be so out of character for him, yet at the same time, it could add a whole new dimension to his character, showing a more artistic and emotional side that we haven't seen much of before.
I think Naruto would be really interesting. His never - give - up attitude and his large array of jutsu would be very different from what the Mortal Kombat characters are used to. He could introduce the concept of chakra to them and his shadow clone jutsu could really throw them off in a fight.
Rock Lee from Naruto would be a great choice. His dedication to martial arts and physical combat would fit well in the world of Baki the Grappler. He could have some intense battles and learn new techniques from the Baki characters.
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.
I think Naruto and Bugs Bunny would be a great pair. Naruto's determination and Bugs' laid - back but clever attitude would contrast well. They could play off each other's strengths and weaknesses, with Naruto providing the brute force when needed and Bugs using his quick thinking to get them out of tricky situations.
Scorpion from Mortal Kombat could be a very interesting character in this crossover. His hellish powers and his quest for revenge could put him at odds with some of the Naruto characters. His battles with Naruto or Sasuke would be intense, especially with his ability to teleport and use his kunai chain.