User blog comment:JetGatlingGun00/Testing Your One Piece Knowledge/@comment-4004918-20120129210002/@comment-53539-20120129224230

Helmeppo was morgan's son, however, was not working for the Marines or for his father when Luffy first arrives. Once his father left because the spoilt brat had lived off his fahter's image and now his father was disgraced and went to prison the highlife was over. Helmeppo only joined the Marines because he was forced to.

If he wasn't working for Morgan, then he wasn't Morgan's subordinate...