Driftveil City Pokémon Gym Leader: Clay "The Underground Boss"
Inside Driftveil Gym, there are a number of elevators that are in the mine shaft layout which must be navigated up and down and girders which need to be crossed to reach the central elevator, which will take the player down to Clay at the bottom of the mine shaft. There are several Trainers on the way down.
One of the Trainers in the Gym mentions that the depth of the Driftveil Gym helps to remind Clay that he once started at the bottom with nothing.
The Driftveil Gym made its debut in The Mighty Accelguard to the Rescue!; however, only the outside of the Gym was shown in this episode due to Clay being too busy to have his Gym battle with Ash.
The inside of the Gym made its debut in Battling the King of the Mines!. Like in the games, the battlefield is located at the bottom of the mine shaft, requiring an elevator for access.