Galden commands the Dark Knight Steru, a mechanized Magic Swordsman Material unit that class-changes into Rune Knight Steru when its sword embeds a Spirit Stone. As an antagonist, he pursues dominion over Earth's Tear through dark magic and swordsmanship. His combat fuses dark magic with electrical discharges, unleashing attacks like "Raidas Blade" and "Raidas Sword" to summon dark lightning from his weapon.

Bound to the Hell Dragon Clan, he operates under Rigel while ultimately serving the masked Hell Dragon Emperor as the faction's supreme leader. Despite his ambition, Galden reveals vulnerability in fevered dreams of his mother, weeping openly while unconscious and tended by protagonist Sarutobi.

His narrative diverges across adaptations: the manga portrays him as an unrelenting adversary without redemption, while the anime depicts a Heel–Face Turn, transforming him into an ally by the finale. This anime evolution upgrades his unit to Rune Knight Steru, amplifying his lightning assaults and adding pectoral chest beams.