Gloomhilda, also known as Glumilda, is a central antagonist in the anime. Her background is that of a former ruler of the Galaxy of Oz, where she once maintained her empire through fear and terror. Her reign ended when the scientist Dr. Oz used his knowledge and technology to liberate the galaxy, forcing Gloomhilda into exile on its outskirts. From there, she amassed an army of Skeezer forces, plotting to reconquer her lost dominion. An initial sneak attack to reclaim power fails largely due to the unexpected arrival of the protagonist Dorothy, who lands in the Galaxy of Oz during a space battle.

In terms of personality, Gloomhilda begins as a scheming and power-hungry villain, yet she possesses a likable and occasionally humorous side. She is depicted sneering at soap operas, a detail that adds a layer of mundane petulance to her character. Her primary motivation is to obtain the three legendary magical crystals: the Crystal of Love, the Crystal of Wisdom, and the Crystal of Courage. According to ancient legend, whoever possesses all three crystals will rule the Galaxy of Oz for all eternity, and acquiring this power is the driving force behind her actions.

Her role in the story is that of the primary antagonist as well as a foil to Dorothy. She commands the Skeezer forces and travels across various planets in search of the crystals, frequently coming into direct opposition with Dorothy and her companions: Chopper, Plantman, and Lionman. A key relationship that defines her character is with her mother, the Wicked Witch of the West, whose spirit is imprisoned within Gloomhilda's necklace. This connection deeply influences her motivations and ultimately forces a critical choice. Her other significant relationships form with Dorothy’s group; through their repeated encounters, she begins to develop a begrudging respect for their unity, determination, and loyalty to one another.

Gloomhilda undergoes a significant character development arc. Initially focused solely on regaining her power, her perspective shifts as she observes Dorothy and her friends. This evolution culminates when, after her mother is freed and attempts to use the Rainbow Crystal's power for total domination, Gloomhilda openly defies her. She declares her admiration for Dorothy’s team, stating she is moved by how they love and support each other. In response, the Wicked Witch of the West uses the crystal's power to turn Gloomhilda into a stone statue. This act of defiance, however, is the pivotal moment of her redemption. After Dorothy retrieves the petrified Gloomhilda and the crystal, the combined goodwill of the group defeats the Wicked Witch, and Gloomhilda is restored. By the conclusion of the story, she has transformed into an ally, joining the group to bid farewell to Dorothy as she returns home.

Regarding her notable abilities, Gloomhilda is a witch who commands a degree of magical power and authority, allowing her to lead an army and be a credible threat to the galaxy. Her most distinctive ability is not a specific spell but her connection to the imprisoned Wicked Witch of the West, whose power is a latent asset. Furthermore, she demonstrates a strong capacity for leadership and strategic planning in her persistent quest to locate the legendary crystals. Her ultimate act of power is her defiance, which, while resulting in her petrification, proves to be the moral turning point that allows for the Wicked Witch's defeat. Commentators have noted that while her change of heart feels somewhat sudden in the condensed film version, the original television series provides more space for her growing respect for Dorothy to develop naturally.