Clay, the Driftveil City Gym Leader in Unova's Pokémon League, commands Ground-type Pokémon. A miner by trade, he relentlessly pursues capitalist ventures and exhibits impatience with interruptions to his money-making activities. He operates mines outside Driftveil City and initially dismisses challengers lacking fundamental knowledge, like the purpose of Revival Herbs, deeming them unworthy of his time.

Known as the "Miner King," Clay personally excavated and expanded the Driftveil mine in his youth using only a pickax and his Excadrill. This history fuels his criticism of younger trainers aspiring to become Pokémon Masters without demonstrating comparable dedication to hard work. He is the father of Lacey, who attends Blueberry Academy. Unverified lineage suggests a potential ancestral connection to Lian.

During a Gym battle deep within the mine against Ash Ketchum, Clay questioned Ash's work ethic and readiness, framing the encounter as a test of perseverance. He employed a team including Krokorok (for its sand-creating abilities), Palpitoad (for type advantages), and his signature Excadrill. Ash's victory earned him the Quake Badge and partially shifted Clay's perspective on younger trainers' capabilities.

His known Pokémon partners are Excadrill, his constant companion during mining operations and most trusted partner; Krokorok; and Palpitoad.