Da Ji is King Zhou's concubine who was infamously known as a vile woman who enjoyed torture. In various folklore and Fengshen Yanyi, her real form is a nine-tailed fox spirit who possessed a female human named Su Daji.
Based on conversations with the other Mystics, Da Ji is a runaway immortal being who was bored of her previous life. Sympathetic with the serpent king and wanting to entertain herself, she unleashed Orochi from his prison and agreed to serve him. Acting as his main strategist, she uses her schemes and sorcery to inflict confusion in battle. She coordinates their army's advances and personally orders Orochi's minions. She also doubles as the army's inventor as she created the cannons surrounding Koshi Castle. During Orochi's story, she helps plan her lord's rise to power as they defeat each of the reigning factions one by one.
During the final conflict with Orochi, she survives the assault and flees from the battlefield. Sometime after the battle, she meets Himiko and, knowing that she is the key for her lord's resurrection, fiercely guards the girl's safety. They travel together to find Kiyomori, who is interested in reviving the serpent king. By this time, Taigong Wang and his comrades have recovered from their previous defeat and join with other factions to capture her. She sacrifices her own safety to ensure that Himiko reaches her destination and escapes to serve the resurrected Orochi.
In Musou OROCHI Z, she cons Benkei into joining her group and joyfully pits Yoshitsune against his friend at Mikatagahara. She also has three dream stages in this title. In one of them, she teams with Xing Cai and Gracia to prove women's might to the men of the world. One of the new Dream Stages details her betrayal of the Mystics at the Wuhang Mountains, where she frees Orochi from his jail, and defeats the encroaching armies of Taigong Wang and the other mystics, who try to stop Orochi from merging the different worlds. She and Orochi also join the other Mystics in proving their superiority to humanity's best warriors at Chibi.
She is given another Dream Stage alongside Kiyomori, and Orochi X, where they are sieged by all the major factions that have opposed them in Warriors Orochi 2.
During the original timeline in Warriors Orochi 3, Da Ji enjoyed demolishing humanity with the serpent forces. At the battle with the Hydra, she prepares to kill the surviving generals, when Kaguya saves them. She doesn't feel threatened until the coalition from the future uses time travel to prevent the original timeline from occurring. Since Taigong Wang knows Hydra's true identity, he instructs his human companions to capture her. Although Da Ji manages to escape their clutches with her tricks, she is unable to completely evade Nezha and the mystic forces at Sekigahara. Saved by Hanbei and company, Da Ji agrees to cooperate with them upon realizing that they have Himiko in their trust.
Once the coalition reunite their separated regiments, they desire to find a way to go further back in time before Hydra appeared into the dimensional realm. But no human within their midst is viable for the feat. Also, the other immortals who are present -Taigong Wang, Zuo Ci, and Kaguya - had lived in the mystic realm until Hydra appeared. Only Da Ji remained in the dimensional world the entire time as she is the only way out of the rift created by the Hydra, meaning that the coalition has to rely on her for them to save the future. As the coalition returns to her past to prevent Hydra's appearance, they additionally have to protect her from the anti-Orochi forces or risk losing their sole chance of changing the timeline.
Using the coalition as her bodyguards, Da Ji discreetly recovers Orochi's corpse and hides it within a box for her safe keeping. She schemes to kill two birds with one stone: she wants to resurrect Orochi and restore his consciousness. A sane Orochi would have full control over his powers and thereby prevent Hydra from appearing. Da Ji even tries to defend his body from Susano'o, but her plans fail when the giant serpent inevitably emerges. Unattached to Hydra, Da Ji willingly helps humanity defeat it. Although she admits it in private, her perceptions towards human have changed thanks to the time she spent with them.
In one of the downloadable scenarios, "Lu Bu's Revenge", Da Ji and Achilles help Lu Bu in finding and defeating Nezha.
Da Ji and her cohorts are beckoned to a mysterious stone in Ultimate. Not wanting to be at the Coalition's mercy again, her party opposes the heroes who had tracked them. Once Da Ji and company approach the stone, it creates various doppelgangers. With Tamamo free from her prison, Da Ji joins forces with her and they use the artifact to create fake versions of the heroes. Their schemes confuse the Coalition, causing them to momentarily turn against each other in a civil conflict. The deception is lifted thanks to the other mystics' intervention.
After the conflict, she look at a shard of the Divine Mirror and continues to insist she doesn't like humanity and leaves with Himiko. After the past is changed again and the coalition corners Tamamo in Itsukushima, Da Ji shows up to teleport Tamamo to let her escape. As a result, Da Ji is captured and Fu Xi decides to send her back to the mystic realm.
Escaping into the distorted world created by her lord in Warriors Orochi 4, Da Ji recruits Lu Bu and Seimei Abe to join her in aiding Odin, who promises the revival of Orochi. Recruiting an amnesiac Himiko to her cause, they are eventually able to defeat Shuten Doji, and have Odin revive Orochi. To her disappointment, she finds that it is only the God of Destruction in the manifestation of Orochi X that is revived, and not her actual lord.
Nonetheless, she continues to aid Odin until the God of Destruction is defeated and destroyed by the real Orochi, who was revived from Shuten Doji's remnants. Having had her fun, she briefly aids the real Orochi, before taking her troops to join the Coalition, not wishing to be destroyed until the next revival of her lord.
She later joins Hideyoshi's hunt for a beautiful yet shy goddess.
In Ultimate, she is still the de facto leader of the Demon Army, still allied with Odin, but more independent thanks to the revival of Orochi X. She continue to defy the Coalition numerous throughout their search for Odin's soul. When the Coalition near Odin's soul at the Spring of Mimir, Da Ji has noticeably distanced the demon army from Odin and has taken up camp at Kanegasaki with Orochi X. Rather than allow the God of Destruction to continuously give Odin power, the Coalition moves to attack them just before dealing with Odin. Like in the first scenario, Orochi X and the real Orochi are both slain, and the demon army joins the Coalition to stop Odin's plans of destroying all other than himself.
During the alternate scenario where the real Perseus is revived and exposes Hades's deception to the Coalition, Da Ji leads reinforcements for the Coalition at Changshan when they attempt to protect Kaguya and Gaia in order to travel back in time to rescue Odin.
In the new side stages, she is first given a new scenario early into her alliance with Odin, where they are tasked with finding the Arms of Ouroboros at Kyushu. Although she doesn't find the desired objective, she is able to find and wage battle on her former acquaintances in the Date army during their stay in the area, as well as gaining the services of Yoshitsune and Benkei. The second stage she is given is where she and the rest of the demon army under the Coalition defend Ōsaka Castle from Odin's army. Although Odin is able to temporarily distract them with illusions of Orochi and Orochi X, the demon army are able to to push the god back. She also appears during the mock battle between the gods and the mystics, injecting the demon army into the battle in order to amuse themselves.
And she is reprised by Stephanie Sheh in the English dub and Mami Kingetsu in the Japanese dub.