Based on a YouTube comment chain.
For many many Aeons, I waited here, trapped, in this lonely void. No Up, no Down, no Left, no Right, not even time. Only through one point am I allowed to return.
Through a twisted maze, and a remote and abandoned path. Almost no one shall ever find the forbidden fourth lake. Even less make it through the ever-changing Labyrinth.
And None Shall Ever survive the end.
I strike from the shadows. I am fear, I am Hatred, I am CHAOS! I was trapped for my destruction. I AM DESTRUCTION! Any who come to my world perish by my hand. None shall live, all shall die. I am terror incarnate. One you come, there is no escape.
Soon I will be free from the shackles of this realm, and still remain true to form. Master has taken all my true power. But one day, I will return, and bring the final hour!
I, am Giratina.
Then, one day, a trainer appeared. He looked at me, with his eyes hiding in the shade of the cap.
He should have run at that point. He did not even shift his foot position. Not even show a shred of fear.
He had made it through my realm. This was a feat in itself. But, he would die like all others.
He sent out an Infernape. I have seen many, and this one had no exceptional looking features.
"Blast Burn." The trainer ordered.
The inferior creature struck first with an Inferno of Flames. This struck me, and knocked me back. I then countered with my Earth Power. That struck it, and it fell over, not fainted, but on the end of it. I would make sure it wouldn't Recover, as I cast a Heal Block on it.
It weakly gets up, and uses Shadow Claw, wounding me.
THAT TRASH! With all my fury, I Slash the damned creature into a bloody shape. It shall die as soon as I deal with its trainer.
He simply retrieves the fire monkey, the next Pokémon it sends out he calls 'Shaymin'. All I see is a small green hedgehog creature. Such is an insult to send against me, the ruler of the Torn World!
"Here Shaymin." The trainer says, pulling out a flower. As I prepare to strike, the near emotionless trainer has his Pokémon touch the flower. In a flash of light, it turns into a white, slender reindeer.
"Uraaaarrrraaaaaaa-aaaaaaaaa!" I screamed while slashing at the reindeer creature. But, the grass hedgehog simply jumped out of the way, and flew into the air.
"Seed Flare" The trainer said. With almost no time to react, i felt the sting of fire on my back, yet filled with nature energy.
I WILL NOT STAND FOR THIS!
With glee, I watch as the wretched Shaymin falls to the ground by my Slash.
"Shaymin, Return." The Trainer said.
A colourful swan creature envoloped in light erupted from the Pokeball. Too bright a creature to be in my realm.
"Psycho Cut!" the Trainer said, starting to get some emotion.
A blade of energy came into me, cutting at my skin. A Psychic Type! Perfect!
I just had to disappear, use Shadow Force, become one with the shadows. Soon I would defeat this creature, no problem. As I disappeared, I heard.
"Cresselia, Use Protect!"
That would be useless.
My Shadow Force attack hit through the shield, and knocked Cresselia out.
"Go, Diagla" The Trainer said. But, that was impossible, as Diagla was a legendary Pokémon, like me, created under Arceus. But, the Trainer had sent out the metal Dragon.
"Diagla! How have you been captured by humans!?" I roared.
"Roar of Time!" The trainer ordered.
"Join me Giratina." Dialga said, charging his attack
"NEVER!" I bellowed. Impossible. This, creature, had poisoned Diagla's mind! How, could just a boy, no more of eleven years of age, tame time itself?
But fate had different plans. I took Roar of Time head on. But this gave me the advantage, as Diagla was immobile. I struck with Earth Power, and kept on attacking.
"Flash Cannon, NOW" The trainer had said.
Light.....the painful light! It hit my eyes, and it hurt. I must defeat Dialga, and free him from this child. My Earth Power struck, and Dialga fell.
"GO! Palkia!" The trainer said. His voice was becoming distorted. It couldn't be my imagination. Palkia came out, and now, things were just horror.
Horror? No.....I am horror, I can't feel fear!
"SPACIAL REND!" The trainer ordered.
"RAAAAAGGGGGHHHHHH!" Palkia screamed as he fired his attack. I used Shadow Force to escape. Palkia would go down, then his trainer would fall. They would go free!
My attack hit Palkia, and it went down. His next Pokémon couldn't be anything more horrifying then what I had seen.
"Go" the trainer muttered, his image and voice so horribly distorted, but twisted in such a way that I could understand everything. "Darkrai." What he sent out next was a creature of darkness, with a night black body with red and white parts.
For what I thought were the last moments of my life, I for the first and last time felt pure terror as the darkness that I was supposed to rule over consumed me. It became my enemy's weapon, and slowly choked me.
I thought I had been killed, as I had did to the many others who came my way. But, I woke up with the same trainer who had trapped me looking at me. But, he was large, much larger than me.
"Come on out" he said.
For the first time in millennia, I saw something other than the horrible darkness of the Torn World. I saw the real world. That Trainer had enslaved me.
My body had changed,
I now walked on six legs, and I had no Idea were I was or how to get to my world again.
An 11 year old boy, controlling me! I would not have it! In fury, I attempted to lash out at the boy. But, I couldn't. Was I feeling mercy for this worm? No, it was friendship.
That couldn't be! I was hatred! How could I wish to serve a mortal? This was impossible! But, this boy had something about him. Something that made me want to befriend him.
Slowly, my mind was skewed until I could no longer feel the rage I once felt.
I am Giratina. I travel this land with my Trainer, and his partners of Time, Space, Dreams and Sky Flowers. My heart as altered as my form, I am Giratina, and your death shall not be mourned!