From Bulbapedia, the community-driven Pokémon encyclopedia.
Daniel shows in Pokémon Trading Card Game online for the world championships in Trainer Challenge.
"Daniel has been playing the Pokemon TCG competitively since he was 12. He's attended the World Championships several times, and he placed 61st one year. Though he's pursuing a PhD in Political Science, he still takes time out to practice the violin...and play Pokémon.
In the City Championship
Officially, Daniel uses a Lightning and Fighting deck. However an unresolved glitch in the game causes him to use a Grass and Fighting deck in the first battle the player has with him. When in the playoffs, he uses his Lightning-Fighting deck.