Chinatsu Hayase

早瀬千夏,

Age: 14
Birthday: March 30
Height: 163 cm

She is the younger sister of Masamune Makabe and currently attends middle school as a second year. She does not possess the same surname as her brother due to Masamune's choice of changing from Hayase to Makabe.

(Source: Masamune-kun no Revenge Wiki)