The first step in completing this quest is to obtain a Plane Shard. Simply participate in the closing of any rift. In order to obtain the shard you should start participating when the rift is at level one, sometimes you will get credit for a rift that is already started and is at level two but not always. Once you have the Plane Shard head to someplace that is safe from monsters and use the Riftblade Soul Net. Nazim will spawn and after you have laid him to rest the quest will be complete.