From Bulbapedia, the community-driven Pokémon encyclopedia.
Yōsuke is a member of Team Great Rocket from Template:Card GB 2. He's one of the Trainers in the GR Psychic Stronghold.
His deck, Bad Dream Deck (Japanese: バッドドリームデッキ), focuses on Pokémon. He refuses to duel against the player unless this has at least six Gastly and Haunter cards in total (Dark Haunter cards do not count).
When defeated, he gives out one of both We Are Team Rocket and Legendary Power booster packs.