I Have a System, So Why Am I Still Not the Protagonist?

What does it mean to be a protagonist?

Transmigrating? Having a System? Ye Bufan had all that, so why was he still denied a protagonist's fate?

Just as Ye Bufan was miserably scraping by, taking life one day at a time, he came across a girl named Xiao Yan'er. Her father had died when she was young, her eldest sister was disabled, her second sister had only a few years left to live, and, most importantly, her master and mother had been kidnapped by an organization called the Soul Sect.

At that moment, Ye Bufan finally understood what a true protagonist was. He also finally realized that he had transmigrated into a yuri world.

Take Han Feiyu, for example, who always liked to shield everyone behind her, or the girl whose older sister dug out her Supreme Bone when she was young...