蛍乃 千鶴

Haruki's sister who is four years older than him. She is a fashion designer for the brand "HOTATURU" which she founded herself. Although her brand is well-known overseas, it is still relatively unknown in Japan.

At work, she looks like a dignified, attractive, and mature adult, but at home, she becomes a lazy, good-for-nothing woman. Since she cannot wake up by herself in the morning, and unable to do housework, she relies on Haruki most of the time. When she is occupied with work, she sometimes throws a tantrum, and wants Haruki to spoil her like a child. Even so, she likes to play prank and is full of mischief, fond of teasing and agitating other people. She does not have the dignity of a grown-up at all.