Delta Species

EX Delta Species, released in October 2005, is the 27th set of cards in the Pokémon Trading Card Game and the 11th set released by Pokémon USA. It contains 113 different cards. While this set was released after EX Legends hit in Japan, it was released before Legend Maker in English-language territories. The set, which in Japan was named "Researching Tower of Holon", is set in the research centre, Holon. Its logo/symbol is Holon Tower, a tower with a broad top floor.

This set introduces "delta species" Pokémon, which are unusual types. (For example, Tyranitar would typically be a Dark- or Fighting-type Pokémon, but Tyranitar δ is a Metal/Fire dual-typed Pokémon.) It also introduces the staff of Holon Tower and their Pokémon. The Holon staff appears in the form of Supporter cards, all of which require a card to be discarded in order for them to be used, and Holon's Pokémon, which can be used as either Pokémon or as Energy cards.