The central protagonist of the saga. He progresses from a trainee under Ultraman Leo to a seasoned warrior who defeats Kaiser Belial twice, hosts Run to conserve energy in a sun-deprived universe, and ultimately attains the form of Ultimate Zero. He also battles the impostor Darklops Zero during the side story incidents.
Zero is the primary target of Darklops Zero, a mechanical impostor created to eliminate him.
Helodia actively restrains and controls Darklops Zero to manage its destructive power.