So I'm a black mage who has completed the Zodiac Relic line for the Stardust/Lillith Rod and I heard you could buy replicas of each step from Drake in North Shroud as long as you possess a Zeta weapon. I've not been seeing any option like that on Drake. I've tried putting the relic both in my inventory and armoury to no luck. Pictures here:

Pictures here: http://imgur.com/a/zL2JR