The reason Murayama Yoshiki quit Onixiegao was because he was tired of fighting.

In the hot-blooded action drama "Hot-Blooded Street", Murayama Yoshiki is a very important character. He is a member of the Sanno Federation and a student of Guixie High School. Ghost High School is a school full of competition and violence, where Murayama Yoshiki encountered many challenges and difficulties. In the play, he has experienced many battles, including conflicts with other students, conflicts with teachers, etc. However, as the plot develops, Murayama Yoshiki gradually grows up and begins to reflect on his own behavior and values. He began to realize that fighting and violence would not solve the problem, but would make it more complicated and worse. In the end, Murayama Yoshiki decided to quit Gui Xie Gao to show his renunciation of violence and fighting.

In short, the reason why Murayama Yoshiki quit Ghost High School was that he was tired of the fighting here. He hoped to stay away from violence and fighting by dropping out of school and pursue a more positive life.