Ibaraki-Douji is an oni from Japanese Heian-period folklore who commanded the oni of Mount Ooe as their true leader, not Shuten-Douji’s subordinate. She directed guerrilla warfare with strategic skill until Shuten-Douji permitted Minamoto-no-Raikou and the Four Heavenly Kings into their stronghold, causing near-total oni extermination. Ibaraki-Douji alone survived, later losing her arm to Watanabe-no-Tsuna at Rashoumon before reclaiming it and vanishing. She possesses blond hair, scarlet eyes, and prominent forehead horns. Her attire includes a floral-patterned yukata loosely fitted with a wine-colored sash tied in a bow, and large black bead earrings. Blood-red hands and feet display tribal tattoos fading into pale skin, while she wields a great blade forged from bone and curses. Ascensions alter her hair into fiery wings and add feather crowns, shimenawa ropes, and black strips tied around bare insteps. Ibaraki-Douji embodies oni duality: she consumes humans yet enforces order among her kind. Trained by a noble oni mother, she governs with an iron staff—exempting Shuten-Douji—and avoids senseless slaughter, behaving like a wild animal rather than a chaotic monster. She exhibits childlike excitement for sweets and novelties but remains perilous to those offering them. Her deepest devotion is to Shuten-Douji, whose happiness supersedes her survival or oni subordinates’ fate. Her Holy Grail wish seeks solely to see Shuten-Douji smile without sorrow. Relationships drive her: she loathes Minamoto-no-Raikou, the Minamoto clan, and Sakata Kintoki for Mount Ooe’s fall. Her bond with Shuten-Douji masks profound affection and joy in their camaraderie. Lighthearted contexts reveal fandom-like fervor for heroic figures, particularly idolizing "Dharmapala Girl" as "Oni Cure." In *Fate/Grand Carnival*, Ibaraki-Douji appears in the "Oni Cure" segment, reacting with exuberance to Dharmapala Girl’s arrival and summoning Shuten-Douji to witness it, showcasing her fervent admiration for heroic archetypes. Her Noble Phantasm, *Great Grudge of Rashomon*, inflicts heavy single-target damage while stripping buffs and reducing defense. Skills include *Demonic Nature of Oni* boosting attack and NP strength for herself and allies, *Disengage* clearing debuffs and healing, *Morph* enhancing defense, and *Violent Oni of Ooe* removing debuffs, healing, increasing critical strength, and boosting her NP gauge when Shuten-Douji is present. Her triple-Buster deck hinders NP generation, and she relies on support to survive enemy NPs despite offensive prowess.