Hym began as an animated Orichalcum lifeform forged by Hadlar through forbidden magic, initially serving as the Pawn Warrior within Hadlar's chess-themed Royal Guard. His humanoid form consisted of silvery Orichalcum metal, presenting a lean, muscular, featureless, and bald figure reflecting his pawn designation.

Initially, Hym embodied a cruel, violent, and fiercely loyal personality, prioritizing battles against worthy opponents and reacting aggressively to any perceived insult toward Hadlar. His combat style mixed honor with ruthlessness, though arrogance led him to dismiss most adversaries as unworthy. This demeanor originated from inheriting Hadlar's passion and fighting spirit during creation. He harbored an obsessive rivalry with Hyunckel, relentlessly pursuing rematches.

Hym's combat prowess focused on close-quarters martial arts, leveraging his near-indestructible Orichalcum body immune to most physical damage and spells. His signature technique, Heat Knuckle, channeled the Kafrizz fire spell into his fists to amplify striking power. Defensively, he minimized damage by adjusting his stance, even against attacks capable of harming Orichalcum like Nova's Northern Granblade. Though considered the weakest Royal Guard member, his "Promotion" ability proved crucial, activating upon Hadlar's death.

Following Hadlar's demise, Hym inherited his master's soul and will, undergoing a physical and metaphysical metamorphosis. He transformed into the Silver-Haired Beast, gaining long silver hair resembling Hadlar's and organic life. This rebirth altered his personality: shedding vengeful obsession, embracing gratitude for his second life, and forging a genuine friendship with Hyunckel. He expressed disdain for later Orichalcum constructs, viewing them as soulless imitations lacking his original team's camaraderie.

In this new form, Hym mastered Light Aura, replacing Heat Knuckle with the more potent life-force infused Aura Knuckle. His physical capabilities—strength, speed, and durability—increased substantially. After initially seeking revenge against Vearn for betraying Hadlar, he allied with Dai's party. He joined Chiu's Beast Battalion, gradually respecting Chiu's leadership despite initial exasperation with his antics, and occasionally displayed humor.

Key battles defined his arc: surviving Hyunckel's Bloody Scryde, defeating Barbatos for insulting Hadlar, and losing a final rematch where Hyunckel spared him. Hyunckel later saved Hym from Maximum's assassination attempt, solidifying their bond. During the final confrontation with Vearn, Hym's Light Aura proved instrumental against Mystvearn, and his tactical insights aided Popp in identifying weaknesses in Vearn's defenses.

Post-war, Hym achieved full redemption, residing peacefully on Dermline Island alongside Crocodine, Chiu, and Brass.