Guess I'll also go with Pokemon and be a generic trainer, and my best pokemon would be magikarp and I would never let him evolve because I love him.
(queue montage music here) I'll spend years training with my magikarp, winning or losing, we'll develop an unbreakable bond between a trainer and his pokemon. And after months of grueling training I master the perfect skill to beat down my opponents, flail and focus sash.
Then after 2 years of traveling around and beating various trainers and gymleaders around the world, I'll be ready to face on the Indigo Plateau. As I enter the tournament I beat numerous trainers in the group phase of the tournament and emerge to be one of the most unexpected trainer to enter the elimination phase.
I strengthen my resolve and begin fighting my way to the semifinals, until I met that cocky brat and his pikachu.
I managed to beat down his charizard and bulbasaur(weird he didn't choose to evolve it) then he used that damn rat that's been sitting on his shoulder all the time. We've fought numerous pikachus out in the wild and won them without a problem, but this one was different. As it entered the field It's trainer began commanding it to use a move I didn't quite hear,his mouth was moving but no sound was heard and the rat started to glow a menacing yellow and without warning a streak of white burned it's image into my eyes as it descended from the skies. After the smoke cleared all I could see was my magikarp there lying, I tried to return him to my pokeball and failed, my heart felt heavy and time slowed down as I rushed inside the field and as I touched it I felt nothing, my magikarp died that night.
I stopped traveling and battling after that, I came back to my hometown and discovered my magikarp left behind children so I took them in.
It's been 5 years since, and all I've been doing was fishing. It's just me and my 4 magikarps sitting near the river waiting for days to pass by.