Ryo Akiyama, the Legendary Tamer

Digimon Adventure:
Ryo Akiyama became chosen to be a Tamer during the Diablomon crisis of 2000. He was drawn into the Digital World and met his partner Digimon, Monodramon, and teamed up with Ken Ichijoji and Wormmon to defeat the horrific being Milleniummon.

According to the Japanese Brave Tamer games for the Wonderswan (never released in the United States) Ryo later goes on to defeat Milleniummon's incarnations ZeedMilleniummon and MoonMilleniummon; Milleniummon is actually Ryo's true partner--he DNA fuses with Monodramon to create Cyberdramon, and Ryo finds himself in the Digital World of the Digimon Tamers universe. These facts are not considered canon in the Digimon Quest continuity, and aren't even really referred to in Tamers

Digimon Tamers:
Ryo was the undefeated champion of the Hyper Colleseum card battle circuit until his mysterious disappearance. Years later, his successor as champion (Rika Nonaka) and her friends discover that he has been living in the Digital World as Tamer to a violent Cyberdramon. He joins Takato's team over Rika's conspicuously strenuous objections.

Digivice: Digivice Zero; in the Tamer universe, he has a blue D-Power

Sigil Artifact: None.