Pokemon: Cerulean Gym

I wanted to write a Pokemon fanfic but couldn't decide which Pokemon to choose. So, I decided to select a random typing which the MC will be using and that random typing happened to be water. When I thought about water Pokemon trainers the worst gym in the anime came to mind.
I like Pokemon fanfic which has an MC who isn't exactly a trainer but goes on adventures. They may be gym leaders, rangers and even ranchers. So, I thought of writing a similar fanfic with adventure and the development of the gym as the main focus.
The MC is the twin of Misty as I wanted him to be from the same generation as Ash. He will also have a small gift (not aura or psychic).