The COO is the company's Chief Operating Officer, basically the CEO's right hand, and often responsible for various company operations, essentially a CEO without the authority to make major decisions.
At Shanhaiguan, the CEO role was undertaken by Cheng Daqi himself, and when the company wasn't very large, the COO position wasn't that crucial—the position could even be virtually held by a junior college graduate like Xiao Cao—as long as they supervised and carried out the tasks arranged by CEO Cheng.
However, in the time since Cheng Daqi returned to Hua Country, the employee scale at Shanhaiguan had exceeded one hundred people.
A team of a hundred people started dealing with various complex business matters, and as a leader, Cheng Daqi had the ability and the energy to shoulder these responsibilities.