Hild reigns as Daimakaichō, Hell's (Niflheim) supreme ruler and most formidable demon. Only her daughter, the half-goddess, half-demon Urd—affectionately called "Urd-chan"—dares challenge her authority. Hild entrusted Urd to her father Tyr (the Almighty, CEO of Heaven) early in childhood, forging a distant and complex relationship defined by Urd's goddess pride and Hild's unspoken maternal love.

Though often presenting a cheerful and lighthearted facade, Hild hides a calculating, manipulative, and ruthless core. She meticulously engineers events to achieve her ends, exemplified by her counter-plan after being overthrown and imprisoned by Hagall's rebellion. This involved splitting off a fraction of herself as a contingency, left with Keiichi Morisato, to facilitate her eventual return to power.

Hild frequently interacts with Earth through a child-sized avatar, containing a mere fraction of her true might. This avatar acts as a recurring antagonist for the goddesses and directly oversees the demon Marller, frequently employing her in schemes against Keiichi and the goddesses. Despite her antagonism, Hild strictly adheres to cosmic rules like the Doublet System—a pact binding god and demon lives to prevent open war and enforce balance.

Her history with Tyr includes a failed Interspecies Romance Trial cursed by the Ultimate Force, dooming them to fatal consequences should they ever meet, reflecting the enforced equilibrium between their realms. Hild's latent maternal feelings occasionally surface, particularly in worries that Urd's demonic heritage might overwhelm her.

Hild's power consistently surpasses that of all goddesses combined. She wears jewel-based limiters to seal her full capabilities, which encompass reality warping, dimensional travel, and advanced magical manipulation befitting Hell's supreme ruler.