Keep working towards the bottom of the tower, killing the skeletons as Mabinogi Gold
There is rumor that you may have to slay some of the grouped lost souls to get him to spawn. Other Mage classes need this Mabinogi Gold zombie as well, if you group with them, you all benefit and will get the update from slaying the stitched zombie.
After you get the quest update, return to Camtur Flog rattle again for the final step to the quest.
Speaking to Camtur will complete the first part of the quest. When you hail him again he will ask you if you are ready to do the instanced portion.
Say yes, and he will transport you to the top level of a tower, the zombie corpse you retrieved will be lying on the floor beside you your mission is to find an elixir somewhere within this tower.
As you work your way downward through the tower, be careful of a skeleton hidden in the rafters, he is linked to another solo skeleton below and will try to surprise you!
Examine the desk to find that the elixir was once there, but is gone! Keep working towards the bottom of the tower, killing the skeletons as you go.
Talk to Camtur again to complete the Necromancer quest. Now all you need is the experience, get to level 20 and you will finally be, a Necromancer!