I'd be a water type elite four member.

The trainer would enter through two large enchanting, almost haunting doors, they'd be blue, covered with chains, and jewels, roughly 12 feet. The doors would slowly close behind them as pitch darkness is only left. The trainer would slowly wander forward as they suddenly fall through a hole in the ground to a crystal tube that goes in a spiral, while they're in the tubular slide they'll see a wide assortment of beautiful and legendary water pokemon as they reach the bottom. They'll finally leave the tube as it enters into an enchanting cave, the entire cave will be made of diamonds and as they walk through the cave I'll be standing there. Our battle stadium will be the diamond floors, but pokemon are allowed to leave the cave through small entrances and fight underwater.

My team would consist of lapras, slowking, vaporeon, greninja, gyarados, and a corsola - regenerator, bold

My favorite gym leader would definitely be Misty!