Ok, this is a new story, I'm still working on my other ones, but I wanted to do something else, that's how I work usually. This idea spawned from an idea of Ash catching a Grimm and sharing his aura with it, that led to thoughts of Ash's soul getting trapped in the body of a Grimm, which eventually led to this story, completely erasing the idea of catching a Grimm and making a new way for Ash to end up as a Grimm.
Also, just so people know, there will be no romance in this story, so don't ask about pairings.
RWBY is owned by Rooster Teeth, Pokémon is owned by Nintendo.
"If I don't do this the tree will die, and so will the pokémon who live here!"
"I'm not gonna give up!"
"I need to do this!"
"What are you doing!?"
"Stop! That's too much!"
Ash opened his eyes with a growling groan. What had happened to him, where was he? He looked around and realized that he was in a forest of some kind. How had he gotten here? Ash looked around some more and felt uneasy. He could not see Pikachu, May, Max, or Brock anywhere. How had he even gotten here?
Ash suddenly felt a searing pain course throughout his skull as he tried to remember how he had gotten there; as if the memories themselves were sealed off by an impenetrable wall that forced back his every attempt to retrieve them. Ash clenched his head before the pain started to subside and he took his hands off of his head. That's when something about his hands caught his eye; his normal fingerless gloves were missing. Not just that, his hands were pitch black in color. Ash quickly moved his hands in front of his face and was shocked to see that his fingers ended in razor sharp claws. Ash looked down at himself and saw he didn't have any of his clothing; instead he was covered in pitch black fur. He looked around frantically and felt something swishing around behind him. He almost had a panic attack when he realized it was a tail.
Ash ran through the forest as fast as he could before spotting a lake and running over to it. His run slowed to a crawl as he approached the water; dreading what he would see in his reflection, but Ash trudged forward. He knew he needed to look, but without Pikachu or any of his pokémon Ash was almost disappointed with himself for his lack of confidence. With a final burst of determination, Ash forced himself forward and looked into the clear water.
Ash almost jumped back in shock at what he saw, but managed to hold himself in place. He took several deep breaths in an attempt to calm himself before he reexamined what he saw: some sort of pokémon, that much he was sure of, but it was certainly not one he had seen before. Sure he encountered pokémon he had never seen before all the time, but they usually weren't his reflection!
Ash did notice a slight resemblance to Houndour in his new form, but it was only in the basic shape of the head and the dark fur. His new face was covered by what looked like a white mask with red markings on it. Lastly, he took note of his eyes, which were nothing but glowing, blue lights coming out of the 'mask's' eye sockets.
His body was still vaguely humanoid, but he guessed that he could probably move faster on four legs. Ash also took note of the many, jagged, bone-like protrusions coming out of his arms, legs, and back. Ash's attempt to keep calm was also not working very well. He felt like he needed to scream, so he did.
Ash's eyes slowly filled with dread when a scream did not come from his mouth. Instead a loud howl echoed throughout the forest. Ash shuddered before he attempted to say something; he wanted to say 'help' but all that came out of his mouth was a strange growling noise. Ash's new fear was confirmed: he couldn't talk.
How was he going to explain this to anyone? How was he going to be able to tell anyone who he was? Or find any of his friends? Ash's panicked thoughts were interrupted when he heard some rustling in the nearby bushes. Ash warily looked at the bushes, silently hoping it was Pikachu, or perhaps one of his other pokémon, or one of his human companions, but it was not. A creature that looked just like Ash's reflection rushed out of the foliage.
Ash took a step back from this strange pokémon. He wondered if it might have been a transformed person like himself; perhaps even one of his friends. These thoughts were interrupted by about five more of these creatures, all coming out into the clearing and staring at him curiously. Ash took note of one difference between these pokémon and his new body: while his eyes were blue, theirs were all orange.
Ash didn't know why he felt so threatened by these pokémon. They weren't acting particularly threatening at the moment, but something in his gut was telling him to get away. One of the creatures took a step forward and Ash quickly took one back while holding up his hands defensively, giving a few growls in an attempt to say 'stay back' but the strange pokémon did not seem to care about his obvious discomfort towards their approach. Ash continued to hold his hands out in defense when something surprised both him, and the creatures that were approaching him: his forearms and hands began to glow a faint blue color. Ash briefly forgot about the strange pokémon as he stared at his glowing hands for a moment, but the moment was cut short when he heard growling. He looked up to see that the approaching pack of pokémon had taken on a more aggressive demeanor.
Ash barely dodged an attempt by one of the creatures to claw into him as it charged at him. Ash wasn't sure what to do as these pokémon surrounded him, growling menacingly. He was out numbered, and he didn't have any of his pokémon friends with him. One of the creatures tried to strike him again. On instinct he attempted to block the hit with his still glowing forearms, and was surprised when the claws made contact, and no damage was done. Ash didn't know what to think, but he didn't have much time to. The creatures that shared his form were still surrounding him and looked like they were all planning to attack. One jumped forward and Ash swiftly jumped out of its way.
Ash didn't know how he had managed it, but he had jumped quicker and higher than he ever had before. He noticed that the faint blue glow that originated on his hands and forearms had spread all over his body, and he felt powerful. Really powerful, His confidence returned as he felt how fast his body could move, and he bet that he was strong now too. He didn't know what this glow was but it seemed to be helping him, so he wouldn't complain.
Another of the pokémon charged at Ash, but this time he blocked it head on, before swiping his claws down on it and knocking it to the ground. The one to his left jumped at him, but he hit it away with his glowing arm. Ash spun around quickly and pounced towards one of the others and tackled it to the ground before charging off into the forest. The pokémon tried to chase him but whatever this glow was seemed to have made Ash far too quick for them to catch. He lost them quickly, but he didn't stop running.
After a few hours of running Ash finally began to slow down. He gave a few heavy breaths as the blue glow that surrounded his body faded. He glanced around to make sure that no more strange pokémon were following him, and sighed in relief when he found he was alone. Ash looked up at the sky and noticed that the sun was setting. He also noticed he was feeling rather tired after that chase, after another look around his surroundings his blue eyes settled on a large, hollow tree stump.
Ash approached the giant lump of rotting wood and felt a pang of disdain that he forced back. This was not the most ideal place to sleep, but considering everything it would have to do for now. Ash managed to climb into the large stump before curling up in as comfortable a position he could find. He was surprised when he found it was not that uncomfortable. It was not like a bed or anything, but he probably wouldn't have many problems getting to sleep. Ash wondered if his new body had anything to do with that.
As Ash lay there, curled up in a hollow stump, he began to think about what he would do tomorrow. Finding his friends was a no-brainer, but how would he explain what happened to him? What had happened to him anyway? And also, would they even be able to recognize him? Had anything like this happened to them as well? All of these questions plagued the mind of Ash Ketchum as he drifted off to sleep.
And done, I hope you weren't expecting too much, this is only the prologue so it's not even really the first chapter yet, but still, constructive criticism will help me, I know how I want this story to end, and the basic way it will go, but I haven't gotten all the middle stuff worked out yet, and the fact that RWBY episodes are still coming out may affect the course of the story, we'll see what happens, review if you want to.