Hello! Hope you don't mind that I'm going to give you some constructive criticism on your story. I mean, if you do mind, that's okay... =o
In the actual quotes, bold words are corrections in grammar that I made. Other marks in the quotes are explained following each part.
A total of five years have passed ever since that day. The day Pallet Town
's greatest Pokemon trainer set out on his journey, turning 10.
The last sentence really doesn't make much sense, especially the latter part of it: "turning 10" what? I feel that "on his tenth birthday" would be a much better way to phrase it, especially since the next sentence talks about birthdays.
Though age 10 may be the average exciting birthday to all of those new to that age, a legend would come out of this day. This Legend's name is none other than Ash Ketchum.
In Pallet Town, Ash received his first Pokemon, Pikachu, and set out on a journey that would last a lifetime. First setting out through Kanto, Ash's skills were mediocre, but he still had a courageous heart. His greatest foes, who's Team plays a major role in this story is Team Rocket. Now obviously Jessie and James were no problem, buttheir Leader, Giovanni was very suspicious.
I really think that there is no reason to bold Ash's name. Right off the top of my head, I can't think of a good way to set it apart from the rest of the text. Sorry. xP
The underlined part should be rewritten. First of all, you have the wrong form of "who" there. You need "whose" which is the possessive form; "who's" is the contraction of "who is". "Team" shouldn't be capitalized either. I would try "His greatest foe, who play a major role in this story is Team Rocket." "Foe" is singular because "Team Rocket" is one noun, and so "play" has become a singular verb.
Ash would be considered to be a "bastard" child, growing up without a father, only his mother. Always, his father's identity was always questioned. This thought never occurred into Ash's mind during his Pokemon journey, with an expectation for once, when Ash laid eyes upon Team Rocket's Leader, Giovanni, if only for a second while traveling through the Johto Region. The thought of this man was always in the back of his head during his Pokemon Journey.
The two underlined "always" are too close to one another, and had no need to be repeated. One or the other shows us that his father's identity comes up often, so you don't need both. Also, the third sentence of this paragraph seems rather long. I guess one of the problems is that you tell the reader again that Giovanni is the leader of Team Rocket when you already said so in the previous paragraph. Reread your chapter after you typed it to catch this repetitions on your own.
The Rocket Leader had always been watching Ash, and his battling skills.
After winning the Sinnoh League Competition, Ash's first League Winning victory, summoned great pride, determination, and power within him. The young trainer decided to go back to Pallet Town to rest for awhile, now at age 15.
He sits outside in Pallet Town with his Pikachu, not expecting his greatest test to soon arise.
Just grammar nitpicks here. The underlined comma is not needed. The underlined "winning" is also not needed, because "victory" tells the reader that he won.
Really, this was all just things that a simple reread over would have fixed. Not too shabby.
The other problem that I have with your prologue is that it just seems to be a summary. Possibly a better way to do this was to have Ash returning home and thinking back to all he's accomplished, perhaps by having memories resurface as he gazes at objects?
Originally Posted by Example
Ash's eyes fell on the glimmering gold statue he won from the Orange League. He remembered traveling though the archipelago with Misty and Tracey. It was a "fun time in the tropics", and Ash was slightly disappointed to see it end. But the adventure ended with his victory in the Orange League against Drake! It was the first time he won against that powerful of an opponent.
That's kind of what I'm talking about. Have sensual reminders to help bring up memories. This also will shed a light into Ash's thoughts, depending how deep you go. It's also much better than just telling the reader what happened.
That's really my only problem with your prologue. There wasn't much more description you could have thrown in. (A physical description of Ash would be done in action, instead of just a summary. So there's no need to worry about that in your prologue.)
Good luck to you in your writing! ^^