This achievement is gained upon defeating the following rare monsters in Chardok:

an Alchemist`s Acolyte
Arch Inspector Nibi`zi
Battle Master Ska`tu
The Bridge Keeper
Captain Di`ouz
Deathfang
Drill Master Dih`roul
Foreman Ku`lul
Foreman Mirt`akk
Grand Herbalist Mak`ha
Grand Lorekeeper Kino Shai`din
Grave Master Zo`lun
An Iksar Trustee
an Imperial Gravemaster
Interrogator Gi`mok
Kennel Master Al`ele
Korucust`s Courier
Loremaster Piza`tak
Observer Aq`touz
Overseer Dal`guur
Sarnak Collective Auditor
a Security Advisor
Underboss Myli`ki
Watch Captain Hir`roul
Watch Sergeant Riz`oul
a Wizened Herb Collector