GZ began as a mercenary Iron Soldier within a dark ice hockey league, retaining his ego while operating on battlefields under Guilloty's command. This included leading an assault on Antarctica's Silver Castle. His past intertwined with Magnum Ace, whom he believed died in their VZ corps unit's destruction. Upon detecting Magnum's survival signal, GZ concluded Magnum had abandoned comrades, igniting violent hatred.

This hatred persisted until witnessing Silver Castle's camaraderie and enduring agony from his shock circuit—a behavioral control device. These events shifted his perspective; he ceased viewing Magnum as an enemy and allowed Silver Castle’s escape. The shock circuit immediately inflicted severe pain, collapsing him. He then joined Silver Castle, where the circuit was deactivated or removed.

Retaining physical upgrades from Iron Soldier modifications, GZ possessed exceptional armor toughness, making him Silver Castle's most durable member. In his first match, he strategically shielded teammates using this resilience. Later, during the National League, he commanded an ice hockey game.

Personality-wise, GZ maintained a stern, disciplined demeanor consistent with his soldier background. He also displayed gentleness toward children, though initially struggled to form a gentle smile before overcoming this. His techniques included the "Soldier Slap Shot" and "Blizzard Slap Shot".

In the OVA sequel *Under the Flag of Silver Light*, Silver Castle adopted violent tactics after acquisition by Universal Corporation. Disillusioned by this corruption, GZ departed alongside Mach Windy and others to seek a new team and challenge the corrupted Silver Castle.

Manufacturing records confirm GZ underwent early Iron Soldier modification, retiring after Magnum Ace. In the *Shippu! Iron Leaguer* Game Boy game, dark forces captured and reprogrammed him, making him an initial boss battle; upon defeat, he became a playable character.