Doubt is a core antagonist within the Orpheus Order during their conflict with Kaito Daimon and his allies. Driven by the Order's shared ambition, he works to distribute perfected Orpheus rings globally, enhancing human brainpower to achieve dominion over those unlocking their potential.

He serves as the designated rival to Gammon Sakanoue, establishing a persistent adversarial dynamic. This rivalry positions Doubt as a significant physical threat within the Order, marked by his confidence and combative nature. His notable physical prowess complements his puzzle-solving role.

Doubt plays an active role in the Order's strategic initiatives, including a critical 5-on-5 puzzle battle against the Phi Brain team where Order members wield authentic Orpheus Bangles. He personally targets Gammon's younger sister, Miharu, by giving her a replica Orpheus Ring, using this act to provoke Gammon and challenge Kaito's group at a stadium. He also directly approaches Gammon with an offer to join the Orpheus Order, exploiting Gammon's frustration over Miharu being targeted; this recruitment attempt is rejected.

Doubt faces significant setbacks. Former POG member Herbert Müller, wielding a genuine Orpheus Bangle, defeats him in a puzzle confrontation. Later events strongly imply Doubt faced considerable difficulties, described as situations becoming "pretty dicey" for him during the season's second half. The circumstances of these challenges and his ultimate fate after the Orpheus Order arc remain unspecified.