It has to be Spike. He's a small dragon in the My Little Pony world. In Mortal Kombat fanfiction, he could use his ability to breathe fire in really creative ways. He could also use his small size to his advantage, sneaking around and attacking from unexpected angles. His loyalty to the ponies would make him a really determined fighter, which would be quite unexpected considering his usually cute and helpful role in the pony world.
I think Voldemort and Fluttershy would be a really unexpected pairing. Voldemort is all about power and darkness, while Fluttershy is the shy and gentle pony. It would be very strange to see how they interact if they were in the same story.
A really interesting plot could be that a powerful villain from Mortal Kombat decides to invade the My Little Pony world. The ponies then have to team up with some of the good - hearted Mortal Kombat characters. Fluttershy, being the kind - hearted pony she is, could try to befriend some of the more aggressive Mortal Kombat fighters and convince them to help protect their world too. The ponies would then have to adapt to the much more violent combat style of Mortal Kombat.
Well, Raiden from Mortal Kombat might be a strong contender. He is a thunder god with incredible powers. In a crossover with Harry Potter, his ability to control lightning could give him an edge. He could use his powers to disrupt the magic of wizards or directly attack them. And his immortality would make him a difficult opponent to defeat, even against the most powerful wizards.
Scorpion could also be a top - tier powerful character in this fanfiction combo. His hellfire abilities and his ninja skills are no joke. In a fight against the My Hero Academia characters, he could easily surprise them with his teleportation and his ability to throw his spear. However, someone like Endeavor with his powerful fire quirk could also put up a good fight against Scorpion.
Starlight Glimmer also has a good chance. She has shown great aptitude for complex magic. After her reform, she could be on a journey of self - discovery and exploration. Time travel could be a part of that as she tries to understand the past mistakes and how to prevent similar things from happening in the future. And she has the determination to master such a difficult magic.
Definitely Deadpool and Pinkie Pie. Pinkie Pie's hyper - active and fun - loving nature would contrast so much with Deadpool's sarcastic and often dark humor. They could have some really wacky conversations and get into all sorts of crazy adventures together.
Sasuke and Rainbow Dash. Sasuke has his cool and brooding nature, and Rainbow Dash is super confident and competitive. They might start off not getting along because of their different personalities, but over time, they could find common ground. Sasuke could admire Rainbow Dash's speed and she could be intrigued by his ninja skills. Maybe they'd have a friendly competition that ends up making them respect each other more.
It could be Akuma. His Satsui no Hado gives him incredible power and his fighting skills are top - notch. In a crossover, he could easily adapt to the Mortal Kombat's more brutal fighting style and use his dark powers to overpower many opponents.
It could be Arya Stark. In Game of Thrones, she has proven to be a highly skilled assassin. In a Mortal Kombat crossover, her ability to change faces and sneak up on her enemies would be a great advantage. She could use her Needle sword and her skills learned from the Faceless Men to take on opponents. And her list of names of those she wants to kill could easily be added to with Mortal Kombat villains.
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.