Ms. Lu, little Yun Zhu's schoolmates and their parents were witnesses to Yun Jian's shocking act in her younger brother's school the last time. The incident of her killing an assassin on the spot of the school's sports day had become the word of mouth.
This was not the main point, however. People were the most shocked about Yun Jian's identity as the Advanced Special Forces soldier in the military. She was Team Monarch's Slashing God!
Initially, she was known as an ordinary citizen—an underage girl—who killed someone! Ms. Lu should have avoided her like the plague after finding out, or simply be terrified when she saw Yun Jian and would even ask the school to expel Yun Zhu because his elder sister was a murderer.
That was far from the truth. With her title as the Advanced Special Forces and Slashing God from Team Monarch, someone like Ms. Lu were not just unafraid of Yun Jian, she saw her as the exemplar of justice.