Initially, when Han Xiao discovered traces of Harmon, he had been overjoyed, immediately going over to recruit him without hesitation. Harmon followed the tribal traditions and was a pure warrior without any guile, strictly keeping to his promises. Or, one could say that his brain was packed only with muscles. In terms of difficulty for recruiting, he would probably be rated as one star.
Harmon had just left his mother planet and needed to form a War League of his own. Thus, the strength that Han Xiao displayed was enough to win the approval of Harmon, and they agreed to a cooperation. He would join the War League whilst Harmon would join his mercenary group. A mercenary would have sufficient opportunities to exercise his muscles, and this was also what Harmon needed.
As such, Harmon could not strictly be considered as one of Han Xiao's officers but rather an ally on level ground.