From Bulbapedia, the community-driven Pokémon encyclopedia.
The Colorless Altar (Japanese: 無のさいだん) is a location found in Pokémon Card GB2: Here Comes Team GR!. Every TCG player at the Colorless Altar focuses on -type Pokémon cards. Unlike most forts on the GR Island, Colorless Altar doesn't have a side room.
Members of Colorless Altar include Samejima, Nishijima and Ishii. When the player has defeated all three, Ishii awards the player with the GR Colorless Coin.