That is where the rules of the Lesser Underworld lie.
"Like you, I feel this Yin Lord Fang belongs to the Spirit-Slaying Bureau. You should take some time to ask around and find out who he is."
Huang Qingque mused, "If we find the right person, treat him well. I will negotiate with him personally. The Lesser Underworld is very special; if it can be completely controlled by our bureau, it will yield miraculous results."
Chapter 469