The title of this article is incorrect due to technical limitations. The correct title is δ Delta Species.

δ Delta Species (Japanese: δ-デルタ種 δ-Delta Species) are a special kind of Pokémon found in the TCG. The term is often shortened to δ, DS, or Delta. They first appeared in the EX Delta Species expansion.

According to the expansion backstory, Pokémon become δ Delta Species upon exposure to electromagnetic waves, which were produced by scientists in Eidolon Forest attempting to locate Mew. Why the scientists chose to use Greek letter δ is debated. While it appears to come from the scientific use to denote a change, the uppercase Δ would of been more appropriate, as it determines a major change. Another common theory is that Delta is the 4th letter of the Greek alphabet, and δ Delta Species are the 4th sort of Pokémon after Normal Pokémon, Pokémon-ex and Dark Pokémon.

δ Delta Species are different to normal Pokémon, as their type is not what they would be expected to be. For example, Rayquaza becomes a Lightning/Metal type. If the Pokémon is a dual type, the secondary type is always Metal. In EX: Delta Species and the first few promo cards, if a δ Delta Species had one of its types changed to something other than Metal, it was always either to Fire or Lighting. This is most likely because in the TCG, Fire and Lightning Pokémon always have the same weakness, to Water and Fighting Pokémon respectively, so by using δ Delta Species, a player could attack with Fire and Lighting type cards without having to worry about that weakness. However, this does not hold true for later promos and the Holon Phantom expansion. In terms of card design, δ Delta Species have a coil design going around their image boarder, and the evobox circle becomes a letter δ, even on Basic Pokémon.

Being a δ Delta Species does not affect a Pokémon's name, allowing a normal Dragonite to evolve from a Dragonair δ Delta Species for example. If a card wishes to reference δ Delta Species, it uses the text "Pokémon that has δ on its card."

List of Sets that contains δ Delta Species

• EX: Delta Species (Japanese's Researching Tower in Holon, and Eeveelution theme decks)
• EX: Holon Phantoms (Japanese's Holon Phantom)
• EX: Crystal Guardians (Japanese's Miracle Crystal)
• The Furthest Ends of Offense and Defense (Japanese - not named for English yet)

Pokémon who have appeared as a δ Delta Species (Normal)

• Charmander (Lightning)
• Charmeleon (Lightning)
• Charizard (Lightning/Metal)
• Blastoise (Fighting/Metal)
• Beedrill (Grass/Metal)
• Pidgey (Lightning)
• Pidgeotto (Lightning)
• Pidgeot (Lightning/Metal)
• Fearow (Lightning)
• Pikachu (Metal)
• Raichu (Metal)
• Sandslash (Fighting/Metal)
• Oddish (Water)
• Gloom (Psychic)
• Vileplume (Psychic/Metal)
• Meowth (Darkness) and (Darkness/Metal)
• Persian (Darkness/Metal)
• Psyduck (Lightning)
• Golduck (Lightning)
• Mankey (Fire)
• Primeape (Fire)
• Kingler (Fire/Metal)
• Exeggcute (Fighting)
• Exeggutor (Fighting)
• Marowak (Fighting/Metal)
• Horsea (Fire)
• Seadra (Fire) and (Fighting)
• Jynx (Fire)
• Electabuzz (Fighting)
• Magikarp (Metal)
• Gyarados (Lightning/Metal)
• Starmie (Water/Metal)
• Eevee (Metal)
• Vaporeon (Water/Metal)
• Jolteon (Lightning/Metal)
• Flareon (Fire/Metal)
• Omanyte (Psychic)
• Omaster (Psychic)
• Kabuto (Lightning)
• Kabutops (Lightning)
• Aerodactyl (Fire)
• Dratini (Lightning)
• Dragonair (Lightning)
• Dragonite (Lightning/Metal)
• Mewtwo (Fire/Metal) and (Lightning)
• Crobat (Grass/Metal)
• Pichu (Metal)
• Bellossom (Water)
• Azumarill (Water/Metal)
• Espeon (Psychic/Metal)
• Umbreon (Darkness/Metal)
• Kingdra (Fire/Metal)
• Larvitar (Fire)
• Pupitar (Fire)
• Tyranitar (Fire/Metal)
• Treecko (Psychic)
• Grovyle (Psychic)
• Mightyena (Darkness/Metal)
• Pelipper (Lightning)
• Ludicolo (Fire)
• Gardevoir (Psychic/Metal)
• Carvanha (Fighting)
• Sharpedo (Fighting)
• Trapinch (Grass)
• Vibrava (Grass) and (Psychic)
• Flygon (Grass/Metal)
• Cacturne (Fighting)
• Lileep (Darkness)
• Cradily (Darkness/Metal)
• Anorith (Metal)
• Armaldo (Fighting/Metal)
• Chimecho (Metal)
• Bagon (Fire)
• Shelgon (Fire)
• Salamence (Fire/Metal)
• Beldum (Lightning)
• Metang (Lightning)
• Metagross (Lightning/Metal)
• Latias (Lightning/Metal) and (Fire)
• Latios (Lightning/Metal) and (Water)
• Rayquaza (Lighting/Metal), (Fire) and (Water/Metal)
• Deoxys (Colorless), (Darkness), (Metal) and (Lightning)

Pokémon who have appeared as a δ Delta Species (ex)

• Tyranitar (Lightning)
• Sceptile (Psychic)
• Gardevoir (Fire)
• Latias (Fire)
• Latios (Water)

Pokémon who have appeared as a δ Delta Species (Star)

• Gyarados (Fire)
• Mew (???)