Katsura, Yukiji

Katsura Yukiji is the 28-year-old sister of Hinagiku. She is a world history teacher at Hakuō Academy and doubles as a 24-hour gate guard. She refuses to let Hayate enter the school when they first meet because she is afraid that letting unauthorized personnel on campus will result in a salary deduction for her.

Her attitude softens after Hayate first saves her from falling off the clock tower, but she still almost causes Hayate to be rejected from Hakuō by unnecessarily making him anxious during his entrance exam. She repays Hayate by telling everyone in her class on Hayate's first day that he is a super cool person.

She has a group of underachieving students (Izumi, Miki, and Risa) who hang out with her a lot. She lives on the Hakuō campus; she tells Hayate that she does this so that she can save rent money and use that money to buy alcohol instead.

It is a recurring gag that she will do anything for money, going as far as to allow an evil spirit to possess her because it told her it would give her a million yen. When Makimura Shiori is sent to teach at Hakuō, Yukiji is demoted to sub-homeroom teacher. She later regains her position as homeroom teacher when Makimura is promoted to a higher position.

In the extras of volume four of the manga, the author writes that before starting the Hayate no Gotoku! manga, he had created a one-shot manga where the story is about a female high-school student and her little sister trying to pay back a 80 million Yen debt, then writes that these characters are, in fact, Yukiji and Hinagiku.