minotaurs dont drop staff pieces, only right skull halves. fight the flesh crawlers and catablepons for staff pieces. and killing 20 is nothing. keep killing. its a semi-rare drop, maybe one in 80 or so oh and when you finally get all the pieces, you have to join the skull halves together, then the staff halves together, then you attach the staff to the skull i think the bottom of staff from flesh crawlers is easy to drop. because i got more than 10 in 20 mins the top of staff from catablepons is hard to drop.