Shuten-Dōji, a formidable oni demon, serves as the narrative's primary antagonist. Her appearance combines beauty and menace—long flowing hair, sharp claws, and a voluptuous figure often highlighted by revealing clothing, which she strategically uses to lure victims. She commands a band of oni from their stronghold at Mount Ōe, orchestrating the abduction of young women from Kyoto’s imperial capital. These captives endure forced servitude, with many ultimately slaughtered for consumption by Shuten-Dōji and her followers, their flesh and blood satisfying her predatory demonic instincts and desire for human subjugation.

Exhibiting sharp strategic intelligence, she employs charm and wit to deceive and outmaneuver foes. Her fixation centers on the human protagonist Mitsuki, whom she attempts to coerce into becoming her bride through relentless psychological manipulation, though Mitsuki resists these advances. As the oni-king of Mount Ōe, Shuten-Dōji dominates Japanese folklore, ruling subordinate demons from her fortress—the Iron Palace within Mount Ōe’s Demon Cavern.