Pokémon, but I'm forced to be a ghost champion

Introduction: In the Pokémon world, there is a young man named Xingye in Weibai Town. He was originally an introverted college student on a certain blue star, but because he accidentally crossed over to the world of Pokémon, with the blessing of the system, he thought he could break out of the world and easily become the strongest in the world.But he found that the system forced him to only tame ghost-type Pokémon...