Volkner first gets mentioned in Challenging a Towering Figure!, when Tower Tycoon Palmer hints to Ash that the Sunyshore Gym Leader's battling skills are sharp enough to really test him.
He finally shows up in person in DP165. Turns out Volkner and Flint go way back—they met as kids, became rivals, then grew into solid friends. Once Volkner took over the Gym, he basically became Sunyshore City's tech guy, designing the city's walkways and infrastructure. He's also responsible for the Sunyshore Tower, which powers the whole place.
For a while though, he got sick of battling. He started just handing out badges to anyone who showed up, unbothered by whether they actually deserved them. But watching Ash go up against Flint reignited something in him—suddenly he wanted to battle for real again, and he agreed to face Ash in a proper Gym match.
Content compiled by AnimeList.moe from publicly available sources.
