Ougi appears a girl with short black hair, black pupils, and pale white skin. She is a junior of Koyomi Araragi at Naoetsu Private High School, as she refers to Koyomi as senpai. She claims to be Meme Oshino's niece.
When she meets Nadeko at the beginning of Otorimonogatari, it initially appears that she merely want to tell Nadeko to stop playing the victim, it is later revealed that she is the mastermind behind Nadeko tricking into becoming a snake god.
Four months after Mayoi disappears, Koyomi has a conversation with Ougi in the classroom. After that, Ougi excuses herself by saying that she has a lot of work to do. When Koyomi asks about her job, she tells him that it's basically a work that involves punishing liars.
Her gender is undetermined as in Hanamonogatari (Suruga Devil), Suruga refers to her as "Ougi-kun," "he," "this guy" and "the boy." She also told Suruga that she has always been a boy since she was born when Suruga asks about it.