Minato Nagase

Minato is Jun'ichi's younger sister. She is a year younger than him and attends the same school as him as a first year high school student. She is capable in all areas of house hold related work and is proud of it. She also has unique abilities, like listening to the ground to detect the presence of animals, as well as be able to communicate with them. She has feelings for Jun'ichi. She mentions that she was an adopted sister once, but later says it was a joke.

Minato is blood-related to Jun'ichi in the PC game, in the PS2 version she is not related to him, and it is unclear as to whether she is blood-related to Jun'ichi in the anime. (Her and Jun'ichi end up believing that they are indeed blood related, although the parents make a comment at the end of the series hinting that they are not blood related.)