Kazamatsuri Koromo

The protagonist's cousin and the elder of the two sisters. Quiet and elegant girl, but is actually a daredevil. Because she has the characteristic of being interested in everything, she is very good at researching and investigating supernatural things. Although her brain reacts very quick, her body can't keep up due to lack of exercise. Since she can experience a lot of interesting things when she is with the protagonist, she always sticks to him and research those things.