Daki was the main antagonist in Demon Slayer’s Entertainment District Arc. She was a demon affiliated with the Twelve Kizuki, and she was the secondary holder of the position of Upper Rank Six, which she shared with her older brother, Gyutaro.
Gyutaro was a demon who belonged to the Twelve Kizuki and held the position of Upper Rank Six, which he shared with his younger sister, Daki.
Gyutaro was a human child who worked as a debt collector in Yoshiwara’s Rashomon Riverbank, the lowest class in the Entertainment District, before he and Daki were personally turned into demons by Doma, who was Upper Rank Six at the time.