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
Digivice: Digivice Zero; in the Tamer universe, he has a blue D-Power
Sigil Artifact: None.