When Takato, Henry, and Rika used their Blue Card, it transformed their card readers into D-Powers, and allowed each of their Digimon to manifest in the Real World. Later, the Blue Cards allowed the Tamers to draw upon the power of Calumon and matrix digivolve to Ultimate. Although the first few Blue Cards appeared randomly, the Tamers are eventually able to transform their own cards into Blue Cards at will, though they usually use Evolution cards. Even Kazu's fake Blue Card works, because it draws on Takato's faith and Calumon's power.
Digimon World 3
The Blue Card is used to go between the east and south sectors. When Junior talks to the tricky Guilmon he gives him a false Blue Card called a 8lue Card. When Junior talks to him again in the basement of the Forest Inn, he gives him a real Blue Card.
|Main characters:||Takato Matsuki | Henry Wong | Rika Nonaka | Ryo Akiyama | Jeri Katou | Kazu Shioda | Kenta Kitagawa | Suzie Wong | Ai and Mako|
|Digimon:||Guilmon and Grani | Terriermon | Renamon | Cyberdramon | Leomon | Guardromon | MarineAngemon | Lopmon | Impmon and Behemoth | Calumon|
|Allies:||Omnimon | Mitsuo Yamaki | Monster Makers | Digimon Sovereigns | DigiGnomes | Alice McCoy and Dobermon | Minami Uehara and Seasarmon | Takehito Uehara|
|Villains:||Millenniummon | Hypnos | Monster Makers | Deva | Mephistomon | D-Reaper | Locomon and Parasimon|
|Relationships:||Takato Matsuki | Henry Wong | Rika Nonaka | Jeri Katou | Ryo Akiyama | Kazu Shioda | Kenta Kitagawa | Suzie Wong|
|Other media:||Battle of Adventurers | Runaway Locomon | Digimon Tamers 1984 | Message in the Packet | Brave Tamer|
|See also:||Digimon | Digital World | D-Power | Digi-Modify | Digital field | List of episodes|