"Little John" Armstrong, born Hiyoshi Gou, is the youngest son of scientists Kentaro Go (Baron Hrothgar) and Mitsuyo Go (Mary Ann Armstrong). His father departed Earth during his infancy, leaving a paternal void partially filled by his protective older brothers, Steve and Big Bert, who often treated him as their playful younger sibling.

His prodigious intellect emerged early, marked by exceptional aptitude in mechanics, robotics, and electromagnetism. Recognized as a prodigy by university professors, he mastered complex subjects like quantum mechanics through specialized instruction. This expertise led him to invent the octopus-inspired robotic companion Tako-chan. His technical proficiency proved vital as the Voltes V team's dedicated technical specialist, handling critical field repairs and maintenance during operations.

Complementing his scientific talents, he excelled in aquatic sports, particularly swimming and diving. These skills were essential for his role piloting the Volt Frigate, Voltes V's leg component, which required expertise in maritime tactics.

His journey intertwined with Earth's resistance against the Boazanian Empire. As a Voltes team member, he defended Earth against alien invasions, utilizing both combat piloting and technical ingenuity. During the liberation of Boazan, he contributed to the rebellion against Emperor Zambojil’s tyranny, aiding the overthrow of the oppressive regime and the end of discrimination against hornless Boazanians.

In the final conflict depicted in *Voltes V: The Liberation*, he joined the unified assault combining Voltes V and the Solar Bird spacecraft. This battle represented the culmination of his established role.

Throughout official media, his identity as a child deprived of his father’s presence remained a consistent emotional undercurrent, shaping his reliance on his brothers and his dedication to the team.