Jack Oliver is a 22-year-old human male support pilot serving with Earth's defense force, Blue Fixer. He operates the transforming spacecraft-turned-combat robot, Baldios, against the invading S-1 Aldebaren Army commanded by Zeo Gattler. Jack possesses no recorded distinctive physical traits like glasses, freckles, facial hair, or smoking habits. His known family consists solely of a younger sister named Emily Oliver.

Within Blue Fixer, Jack combats the S-1 threat, including Gattler's deployment of artificial suns designed to melt Earth's polar ice caps and trigger catastrophic tsunamis. His documented involvement centers on these defense operations during the Earth-S-1 conflict.