General Fire Mountain Mask Magman, also known as Volcano Mask General Magman, is a high-ranking commander within the Black Cross Army who appears as a primary antagonist in the latter portion of the series. He is introduced to replace his predecessor, Iron Mask General Temujin, following Temujin's repeated failures to eliminate the Gorengers. Recruited from the volcanic Eldgja region in Iceland, Magman arrives in Japan to assume command and bring a new, more aggressive strategy to the Black Cross Army's operations.

Magman is a cruel, calculating, and tyrannical despot who leads his own specialized unit known as the Eruption Battalion. He is driven by a desire for global domination and is utterly loyal to the Black Cross Führer, though it is suggested that this loyalty may stem as much from fear as from genuine devotion. He is a highly intelligent strategist and tactician, capable of quickly adapting his plans to counter the actions of his enemies. His pride as a commander is immense, and he becomes particularly desperate and reckless when he loses the Führer's favor, launching a final, all-out assault to prove his worth and destroy the Gorengers before being replaced by Commander-in-Chief Golden Mask.

In the story, Magman serves as the central field commander of the Black Cross Army for a significant arc. He commands from his formidable mobile battle fortress, the Navarone, a heavily armed underground and flying fortress capable of storing numerous Condoler fighter craft. The Navarone is armed with powerful cannons, a flamethrower, and an energy barrier, making it a significant threat. Magman clashes directly with the Gorengers on multiple occasions, proving to be one of their most durable and powerful opponents. His key relationships are defined by rivalry with his predecessor, Temujin, whose interference initially complicates Magman's plans, and by his subordinate position to the Black Cross Führer, whose judgment he ultimately defies in a final act of desperation.

Throughout his tenure, Magman shows little to no development in terms of morality or allegiance, remaining a steadfast servant of the Black Cross Army. His character arc is defined by his rise to power, his struggles to defeat the Gorengers, and his eventual fall from grace and subsequent destruction. As the Führer loses confidence in him and moves to revive the more powerful Golden Mask, Magman's motivation shifts from serving his master to proving his own supremacy, leading him to recklessly engage the Gorengers in a final, decisive battle.

Magman possesses a number of notable abilities that make him a formidable foe. His most distinctive power comes from his volcanic mask, from which he can launch napalm missiles and fireballs at his enemies. His primary special attack is known as the Volcano Mask Rage Eruption. He is a master combatant, highly skilled in swordsmanship with his personal saber, and possesses superhuman strength and durability, making him virtually impervious to the Gorengers' standard weaponry. He can also survive high falls without injury. Despite these powers, his defeat comes in an unconventional manner when the Gorengers use their Gorenger Hurricane technique to transform into an egg. Magman, mocking the tactic, hard-boils the egg using the heat of his volcanic mask and then eats it, only for the egg to explode from within, finally destroying him.