Galdarblog reigns as the primary antagonist, hailing from the realm of Grim Reapers. Leading the Galdarblog family—guardians of the royal lineage—he commands formidable authority and wields the magically potent Demon Sword Tyrfing. His influence extends to Merlo Life Insurance, a pivotal entity in the clash between human and Grim Reaper societies.

Driven by the conviction that elongated human lifespans destabilize natural order, he orchestrates the dismantling of the barrier dividing both worlds. This scheme stems from Grimwald’s escalating energy crisis, fueled by Grim Reapers subverting their original purpose to prolong human lives. Viewing world-merging as the sole path to equilibrium, he enforces his vision through coercive dominance over both realms.

Bound by blood to Ryosuke Kaga and Satomi Kaga as father and husband, his hidden lineage intertwines with the fractured legacy of the sword Gram. His strategic machinations involve adopting a human guise to manipulate Ryosuke and allies, concealing his agenda until pivotal moments.

The climactic clash with Ryosuke erupts into a cataclysmic duel, shattering the interdimensional barrier. Though bested, Galdarblog defends his actions as a desperate bid to avert universal chaos. Post-defeat, his ultimate fate lingers ambiguous, his presence vanishing without trace.

Epitomizing contradiction, he balances tyrannical ruthlessness with warped devotion to duty. Tyrfing embodies his martial might and the devastation wrought by his ideals, etching his ideology permanently into the narrative’s core struggles.