The Combine's Return- EoK Collectibles Achievement
For this achievement you'll need to complete three different zones of collectible achievements; for a total of 12 sets of collections. Reunification (Lceanium), Where the Obulus Once Stood (Scorched Woods) and Trailblazing (Frontier Mountains) are the zones and achievements you will need to complete.
The Combine's Return is one of two achievements that you need for the Empires of Kunark Master Scavenger achievement. Finishing the EoK Master Scavenger achievement will award the player with another rank of Trophy Collector (increases your available Trophy slots by 1) as well as Delicacies Purse, a 38 slot 100% weight reduction bag.