Lady Eboshi is the formidable founder and leader of Irontown, a fortified settlement built around iron production and firearms manufacturing. Her background is marked by survival and determination: she was originally a shirabyoshi entertainer who was later captured by pirates and forced into marriage with their chieftain. She orchestrated her own freedom by assassinating her husband and then used her newfound independence to create a community that would shelter the marginalized. She personally rescued women from brothels and employed people suffering from leprosy, giving them purpose and dignity in a society that had cast them aside.

Personality-wise, Eboshi is tough, confident, and charismatic. She possesses a calm, authoritative presence and a sharp strategic mind that commands respect from her townspeople. She is not driven by greed in a simplistic sense; rather, she is motivated by a genuine desire to build a prosperous, self-sufficient refuge for those who have been oppressed. This ambition, however, comes at a heavy cost. She views the forest and its animal gods as obstacles to progress and is willing to destroy nature to secure Irontown's future. Her pragmatism can be ruthless, and she makes calculated decisions that cause violence and devastation without hesitation.

In the story, Eboshi serves as the primary human antagonist, representing industrial expansion and the human drive to dominate nature. Her actions set the central conflict in motion: she shot the boar god Nago, which turned him into a demon and cursed Ashitaka, and she openly plots to kill the Forest Spirit to clear the land for her ironworks. She collaborates with the monk Jigo, who seeks the Forest Spirit's head for the Emperor, using their alliance to further her own goals.

Key relationships reveal her complexity. Ashitaka confronts her with an alternative vision of coexistence, but she remains firm in her convictions until the catastrophic consequences force a change. San, the wolf-raised princess, views Eboshi as the embodiment of humanity's destructive greed, and their mutual hostility fuels the war between Irontown and the forest. Eboshi's bond with her own people, particularly the women and lepers she protects, is one of mutual loyalty and gratitude. They see her as a liberator and follow her without question.

Eboshi undergoes significant development over the course of the narrative. Initially unyielding in her belief that progress justifies any harm, she experiences a brutal reversal when Moro, the wolf goddess, bites off her arm during the battle over the Forest Spirit. The destruction that follows the spirit's beheading—the spread of a chaotic dark fluid that devastates both the forest and Irontown—forces her to confront the true cost of her ambition. In the aftermath, she expresses genuine regret and vows to rebuild Irontown in a more balanced, respectful way, signaling a shift toward humility and a willingness to coexist with nature.

Notable abilities include her skill as a swordsman, her strategic acumen in both defense and offense, and her expertise in industrial management. She oversees the tatara iron-smelting process and has introduced advanced firearms, which give Irontown a military edge against both samurai and forest spirits. Her leadership is her most powerful asset, inspiring fierce loyalty and effective organization. While she lacks supernatural powers, her courage, cunning, and resilience make her a formidable force in the world of the film.