Introducing herself to her new class beside her friend A-ko.
C-ko Kotobuki (寿 詩子 Kotobuki Shiiko) is a supporting character who has blonde hair.
Parents[]
In both incarnations C-ko only has a single parent shown. In the first, she only has a mother who appears. In the second (where she's 10) her mother had died long ago and she was raised by her adoptive father, who runs Kotobuki Industries.
From the 4th movie
From the 5th movie