Xu Si used to be a servant of the Xu Family. His father, his grandfather, and his great-grandfather all sold themselves to the Xu Mansion as slaves, but as for which province, which mansion, which Xu Family specifically, he couldn't quite recall.
Back when Luo Yin roamed the Central Plains with his brothers, looting and annihilating entire households, servants and lower-caste people were usually not counted as part of "the entire household," except for those fiercely loyal ones who had to be skinned alive. Sometimes, those with decent aptitude, enough courage, or personal vendettas were recruited into the gang, essentially becoming disciples.
This is how Xu Si joined. When his master was being stewed, everyone else fled, but this kid stepped up and took a share, which left an impression on Zheng Zetian.
After consuming that share and becoming a brother of the Luo Sect, Xu Si's "Si" was no longer just one-two-three-four, but became the "Si" of unrestrained and reckless indulgence.
