Can anyone help me find both parts to wave if memory serves one part is found with the shadow dragon but wheres the other part

I can tell you with certainty that it is not with the shadow dragon, though you do get the scales from it, however I know that the Wave Halberd head is from the Sahuagan Prince in chapter 5 I believe. You can agree to talk to the prince to kill the king, then turn around after the king is dead and kill the prince to get the Wave head. Can't help with the shaft though. Still looking fot that myself

you get the shaft when beating the planar prioson, you get it from the warden
the staff sucks anyways so why bother givng 7.500 for it