The subject of this article has no official English name. The name currently in use is a fan translation of the Japanese name.
The Hell's Demon Deck (Japanese: ちていのあくまデッキ) is a Theme Deck from Pokémon Card GB2: Here Comes Team GR! for the Game Boy Color. It focuses on Pokémon and is available from the Auto Deck Machine 2.
The promotional cards in this deck include the Asobikata duo of Diglett and Dugtrio as well as the Masaki Promo Machamp. All of these have unique movesets compared to other cards at the time. The Nintendo 64 promotional "Cool Porygon" card also makes an appearance.