Marduk, a dark wizard from the Principality of Gray, harbored deep feelings for Princess Jane roughly a century before the main events. Jane, however, feared and distrusted him, choosing the knight Theo instead. After Jane's father died, Marduk sought to ease her sorrow by mastering necromancy and resurrecting the king as undead. This act accidentally ripped open a gateway to the underworld, unleashing a catastrophic demonic incursion. Though King Kyle eventually sealed the breach, Marduk faced exile from Gray for his role.

Consumed by bitterness and pledging allegiance to the Demon King Angmund, Marduk dedicated himself to Angmund's resurrection. He forged an alliance with Maria, a former priestess of Lua who had turned to the goddess of darkness after losing faith. Together, they orchestrated the resurgence of demonic forces throughout Orvelia. Marduk saw Kasel, King Kyle's son and potential wielder of the holy sword Eia, as a major obstacle to his goals.

Marduk's ruthlessness was evident when he slaughtered nearly the entire Black Edge mercenary faction as they investigated demonic activity on the Gallua Plains. Riheet, the sole survivor, swore vengeance against him. As part of his plan to revive Angmund, Marduk pursued the holy sword Eia, sealed within the World Tree. His attempt to claim the sword led to a confrontation where Riheet killed him, fulfilling his oath of vengeance.

Marduk's initial resurrection of the Gray king set in motion events that intertwined with key figures' fates, including King Kyle's corruption by Angmund and the battle to prevent the Demon King's return. His actions directly triggered the awakening of demonic threats and fueled the central conflict over the holy sword Eia.