Because they r different side of martial art world?
My guess is Xiao sec eliminated the Bai Cao sect which was believed to be producing those super soldiers pills and selling to the Bai Huang enemy country. And Liu is one of the survivors from that sect. Thatβs why he felt a personal vendetta against them. I think his sect might have been framed. The way he touched the pill and wanted to learn more about it. π€