Rainha da Coroa, the Queen of the Crown, is the self-proclaimed ruler of the Crown Empire and the main antagonist of The Adventures of the Galaxy Rangers. She is a vampire-like despot who controls a vast sector of the galaxy and a large number of planets, and her ruthless, expansionist empire is the threat that leads the alien ambassadors of Andor and Kirwin to seek help from Earth. Her personality is defined by cruelty, ambition, and a willingness to dominate other peoples, and she governs through fear and control rather than cooperation.

Her primary motivation is the expansion and preservation of her empire's power. To keep her agents functioning, the Crown nearly exterminated the Gherkhin, a race of beings capable of undergoing psychic energy extraction, and she maintains a mental link with each of her subordinates, allowing her to extend her presence to any part of her territory. Her forces include a large fleet of ships and brutish soldiers that appear as mixes of humans, aliens, machines, and clones.

In the story, she is the recurring enemy of the BETA organization and the Galaxy Rangers. She captures Eliza, the wife of Captain Zachary Foxx, and traps her mind in a psychic crystal, keeping Eliza under her power while her body remains asleep; this captivity becomes one of the captain's strongest motivations in fighting her. Foxx himself suffers serious injuries while escaping from her before receiving his bionic arm. She also works with other villains, such as the space pirate Captain Kidd, when it suits her interests.

Her power begins to weaken over time as several planets break away from the empire with human assistance, yet she remains a dangerous and calculating presence throughout the series. Her notable abilities include her psychic connection to her servants, her control over a considerable military apparatus, and her use of captured beings and resources to sustain her rule.