Nanami Kirishima is Kaito Kirishima's older sister. Ever since their parents' deaths, she has doted on Kaito and been easily moved to tears. She trusts Ichika Takatsuki to take care of Kaito when she goes on a business trip to Bolivia and leaves the two alone in their house.
Nanami is voiced by Aya Hisakawa in the anime.
The morning Kaito woke up following his encounter with Ichika, Nanami called to him, saying that if he did not get up soon, he would be late to school.