Katsura

Katsura is the Gym Leader of Guren Island's (later the Twin Islands') Gym, known officially as the Guren Gym. He hands out the Volcano Badge to Trainers who defeat him. He is a highly intelligent man who specializes in Fire-type Pokémon.

Katsura likes to make up riddles and use puns even in inappropriate situations. Even so, he is a stern opponent and takes his role as Gym Leader very seriously. He values a keen challenger and makes sure they truly earn their Volcano Badge in battle. He has crafted his battle strategy around his Gym's volcanic location, which suits his Fire Pokémon against its biggest weakness, Water Pokémon.

(Source: Bulbapedia)