• English / United States: Colress
• Japanese / Japan: アクロマ
• Japanese (Romanized) / Japan: Achroma
• Japanese (Trans) / Japan: Achroma

Colress is a Pokémon scientist that works for Team Plasma. He is a very erratic and unstable individual but like all mad scientists, he is very smart. He has no regard for the personal safety or well-being of others especially if it hampers his scientific or personal goals.

The first assignment that Ash Ketchum with the assistance of Looker managed to intervene in was at the Sangi Town observatory. Colress had setup a laboratory there and had been working on collecting Pokémon to use as an organic base. Aldith excited to see the results of his work and just how much electric energy could be amplified so they could control Pokémon. He hoped that if the system operated successfully, the Isshu region would belong to the Plasma Gang. Through the use of special radio waves, the Pokémon's mind would be overloaded, preparing it for battle and raising its combat power to the limit.

Aldith along with Team Plasma Grunts under her control, managed to hold off Looker and Ash Ketchum long enough for Colress to collect the necessary data for his experiment before he self destructed the observatory lab.