When Daki was first introduced, she had black hair tied up in a geisha style. She was known for her beauty in the red district. When she transformed into a demon, she had a flower-like tattoo on her face. After she reclaimed her demon cloth, her hair turned white.
Many years ago, Daki had already gained a reputation for her cruelty, such that senile elders remembered her ill-temper and demand for "hime" to be added to her name.
Two days before Kamado Tanjirou and company infiltrated the Red Light District, Daki was confronted by Omitsu, the manager of the Kyogoku House, over her mistreatment of the staff. When the hostess revealed her knowledge of Daki's past and extended lifespan, the Upper Moon seized her. Carrying her far above the district, Daki mocked Omitsu for her stupidity, labeled her as inedible, and dropped her to her death. Returning to her room, Daki was surprised to see Kibutsuji Muzan. Bowing to her master, she listened as he praised her for her new-found strength, cautioned her against getting careless, and stated his high hopes for her as a special Demon.
Walking with several assistants, Daki passed under Uzui Tengen's watchful gaze undetected in her oiran guise. Later, via her Demonic sash, she questioned Makio about the letters she had been sending. Sensing Hashibira Inosuke's presence, Daki's sash fled.
Daki appeared behind Agatsuma Zenitsu as Warabihime, demanding to know what he was doing in someone else's room, and quickly grew irritated at his lack of a response. She extended this irritation to two girls who tried to defend Zenitsu, insulting the young Demon Hunter before viciously abusing a crying girl for not cleaning a room fast enough. Her anger grew as Zenitsu grabbed her wrist to stop her cruelty.
Daki hit the youth through several walls, threatening him with further discipline, but stopped when the master of the brothel begged her to. Apologizing to him, she ordered Zenitsu's wounds to be treated and the mess from her fit of anger cleaned up. The Upper Moon then pondered Zenitsu's identity, noting he might be a Demon Hunter. Later, in her room, she gloated over the success of her plan, promising to kill and eat all of her enemies.
Daki then appeared behind Koinatsu, seeking to eat her before she left to be married. She was then confronted by Kamado Tanjirou while restraining her fellow oiran, and questioned him about the amount of backup he had, including when the Pillar would arrive. Dismissing the youth for his weakness, Daki soon grew enraged when he demanded she release Koinatsu, and attacked the Demon Hunter with her sashes. Noting that he had survived, she complimented Tanjirou's eyes, wishing to eat them. She briefly clashed with the young Demon Hunter again, noting his skill in only severing the section of sash containing Koinatsu, but confidently proclaimed his doom regardless.
She then expressed irritation at her foes' interfering actions, questioning Tanjirou about his amount of backup again. Despite his refusal, she offered to let him live if he told her, noting that in their brief clash his sword had been chipped. She also stated that whoever had forged the blade was a terrible blacksmith, and quickly grew irritated once more when her opponent denied this, promising to kill him with her next attack. Launching said attack, Daki was shocked when Tanjirou cut through her sashes with a Dance of the Fire God technique. Noting the change in his sword style, she dodged his next attack, countering with an attack of her own. Missing due to another Dance of the Fire God technique, the Upper Moon turned to face her opponent just as his blade struck at her neck.