Du Caidie's boyfriend, indeed, came from a powerful background. He was the son of Stone Sword Edge, Shi Yi.
Shi Yi (石逸) serves as the Si Master in the Dragon Soul Station of Jiangyang. Most of the time, he stays in Jiangyang City. Given that Du Caidie's home was also located in Jiangyang, she had known Shi Yi since high school. After she started her university education, she officially became Shi Yi's girlfriend.
Shi Yi had also introduced Du Caidie to his parents.
Since Du Caidie knew that Shi Yi's father, Stone Sword Edge, held the distinguished position of Grand Marshal in the Dragon Soul Station of Linjiang — a position equivalent to the city's leader, she was not afraid of Su Chengyu at all. One could even say that she didn't care much about the new king of Linjiang, Su Chengyu.
"Brother Yi, where are you? I'm being bullied!"
Du Caidie made a pitiful complaint on the phone.