Hibari Ōzora ( 大空 ひばり , Ōzora Hibari ) is the titular character of Stop ! ! Hibari @-@ kun ! ! . Hibari is a high school student assigned male at birth who look and behaves as a girl , much to Ibari 's dismay.Ch. 2 , 4 , 8 Hibari prefers being referred to as Ibari 's daughter , Ch . 6 , 8 , 15 and have expressed an interest in having breasts.Ch. 6 According to Suzume , Hibari become more feminine after Kōsaku start living at the Ōzora household.Ch. 8 Hibari show an interest in Kōsaku early on , Ch . 9 and continue to make advances toward him throughout the series.Ch. 17 , 22 , 35 Hibari get bolder as the series progress , including openly flirting with Kōsaku at school , Ch . 37 and kissing him.Ch. 18 , 48 , 51 Hibari is extremely athletic and intelligent , in addition to being physically strong despite Hibari 's relatively small body frame.Ch. 5 , 7 , 8 , 22 Hibari is voiced by Satomi Majima .