Riko Fukamine

Оригінальне ім’я: 深峰莉子

Riko is Haruhiko's younger sister by name, though they're basically the same age and even end up in the same class together in school after she enrolls. In third grade, she joined Haruhiko's family due to family circumstances and Haruhiko immediately treated her as if she really were his little sister. When they were younger, she left for several years only to appear again one day out of the blue.