Here is a custom Pokesona I made for my BF. His name is Cut Throat, an abandoned Dragonite for being so abnormal, not even a shiny color.
This particular Dragonite was forced to evolve, much like a certain other Pokemon, retaining the colors from his previous evolution. The result left him "incomplete" and unwanted by his now former trainer. Left to wander the earth in loneliness and despair as well as a hatred for humans, he seeks somewhere far from them. The scars the decorate his body are from the many times he was subjected to harsh training and constantly fending off wild Pokemon as he was the parties frontline. Now an "incomplete" Pokemon, he released and living like any other wild Pokemon would until he spotted something truly interesting.
An odd-looking Ampharos was out in a field with an egg wrapped in her tail, waiting patiently for her egg to hatch. He'd never seen such a Pokemon and went to investigate. He soon learns that she is part of an extraordinary party of Pokemon much like himself. Sadly her party was full of the little one on the way, but he was welcome to join her trainers' friend's party. Before long, they were greeted by said trainer who took a liking to the newcomer. The Dragonite offered up a battle but was turned down. Confused, the Pokemon stood there wondering what was going through this human's mind.
Holding out a lone Pokeball, the trainer offered the Dragonite to join his team because he sees the potential it possesses. Ever the cautious, he accepted his offer and touched a single claw to the ball. In a flash, he was gone, accepting his new trainer. As days turn to months, the young Dragonite was trained to hone his skills and win every battle that came his way. He learned to embrace his "abnormality" and garnered quite the reputation. Living a life of love and care has melted his ice-cold heart and became quite the gentle giant, yet fierce and protective of his "family".
I hope you liked this little story I wrote to be his backstory with the help of my BF.