Chu Mu was unaware of a very important matter.
A message brought by someone sent by Li Hong revealed that the Soul Covenant planned to launch a total attack. They seemed to realize that the Three Great Palaces were producing experts like Chu Fangchen continuously, and if they dragged on, the situation would only become increasingly unfavorable for them.
Therefore, they were searching for an opportunity. The emergence of Wu Kuang had greatly boosted the morale on the Soul Covenant's side. If in the presence of all neutral parties and both sides, Chu Fangchen - representing the strongest of the younger generation from the Three Great Palaces - and the strongest assistant Mu Qingyi, were to suffer a major defeat, the top level of the Soul Covenant would likely leverage this victory to launch an all-out attack on the Three Great Palaces in one fell swoop.
This information came from Li Hong, and Tu Zun Ke Yin received this message just yesterday as well.