Polaris Hilda is the priestess of the Norse god Odin and the ruler of Asgard, a frozen land in the far north of Europe associated with the North Star, Polaris, which she represents. She resides in the Valhalla Palace and serves as Odin's representative on Earth, a position analogous to the Pope of the Sanctuary in Athena's service. Her central duty is to pray continuously to Odin so that the polar ice remains frozen and Asgard's people survive the harsh conditions of their land. By nature she is gentle, kind, and devoted, and she is deeply loved by her subjects.

During one of her prayers, Hilda was approached by a whirlwind of waters that delivered the cursed Nibelungen Ring, sent by Poseidon as part of a scheme against Athena. Although she resisted Poseidon's direct influence, the ring possessed her and corrupted her personality entirely. Under its power, she became a cold, ruthless, and ambitious dictator who set her sights on world domination in Odin's name and plotted to kill Athena and rule in her place. The ring amplified her ambition without limit, turning a benevolent leader into a formidable antagonist, and it also created a dependency that made her alternate between aggression and unnatural calm.

In her role as the main antagonist of the Asgard arc, Hilda summons the seven God Warriors, elite fighters who serve Odin and whose power is comparable to that of Athena's Gold Saints. Each God Warrior carries an Odin Sapphire in his armor, and Hilda commands them to confront Athena's Bronze Saints when they arrive in Asgard. It becomes clear that destroying the ring requires gathering all seven sapphires, which together awaken the legendary Odin God Robe and the sword Balmung. As her warriors fall one by one, Hilda eventually engages in direct combat with Seiya of Pegasus, using the ring's power to unleash energy attacks. Her magical strength is noted to be immense; her cosmos is described as aggressive enough to rival that of the Pope of the Sanctuary and comparable to a goddess's power.

Key relationships shape her story. Her younger sister Freya is the first to notice that something is deeply wrong with Hilda and, despite the danger, reaches out to Athena and her saints for help. The God Warriors themselves are utterly loyal to Hilda, having been chosen from birth to serve Odin, and their devotion renders them blind to the evil of her plans. After all seven God Warriors are defeated, Seiya gathers the Odin Sapphires, awakens the Odin God Robe, and uses Balmung to cut the Nibelungen Ring in two, freeing Hilda from its curse. She returns to her gentle self and immediately prays to stop the glacier meltdown in time to save Asgard, and she asks forgiveness for the deaths of the warriors who fell under her corrupted command. It is later revealed that her corruption was orchestrated indirectly by Kanon of Gemini, who was manipulating Poseidon from behind the scenes, making her a pawn in a larger conflict.

Her development traces a clear arc from peaceful priestess to corrupted tyrant to redeemed ruler. After her liberation she appears as a supporting figure in later events, including the Poseidon conflict and the Soul of Gold story, where she continues to act as Odin's representative. Notably, she is an anime-original character who does not appear in the original manga, yet she remains a significant figure within the Asgard storyline. Her notable abilities include commanding and mobilizing the seven God Warriors, using the ring to fire offensive energy blasts, and wielding divine-level magical power that rivals that of a goddess, including the capacity to maintain the cosmic balance of the frozen north through her prayers.