Number Zero, known as Zero-Go in the Japanese version, is a supporting character in the anime Beyblade X. He is a commentator artificial intelligence associated with X Tower, the venue where official professional Beyblade battles are held. Since the first episode, Number Zero has narrated most of the matches that take place inside the tower, delivering his commentary in a lively and passionate style that matches the high-energy atmosphere of the arena. He is one of several X Tower AIs, alongside companions such as Ichi-Go and Ni-Go, and he is also able to appear in a portable form, which he uses during special events like the Star Battle.

In personality, Number Zero is enthusiastic and expressive. He treats each match as an exciting spectacle, reacting vividly to the action and building anticipation with his announcements. His motivation is tied directly to his role as the voice of official competition: he exists to present battles to the audience, keep track of the proceedings, and give recognition to the bladers competing at the tower. Within the story, he functions as a recurring announcer and observer, providing coverage for many of the most important fights and acting as a constant presence in the professional scene.

Number Zero's key relationships are with his fellow tower AIs and with the professional bladers whose battles he introduces and narrates. He does not participate in battles himself, and his place in the story remains largely functional rather than personal. His development over the course of the series is limited; he stays a consistent fixture of the tower rather than undergoing a substantial arc. His notable abilities include his on-site commentary role, his portable form that allows him to appear beyond the main venue, and his capacity to keep pace with and narrate fast-moving battles.