Story-related, cannot miss.
In order to unlock this achievement, you need to take down the third member of the Order, who resides in Karkh: Al-Pairika.
In order to start this story thread, you need to report to the Karkh Hidden Ones Bureau and talk to Rebekah. This will start the main story mission, “Coins and Daggers” and set you on a path to taking down the Treasurer, in the main quest “Gilded Butterflies.”
The main story missions you need to complete to unlock this achievement are:
Coins and Daggers (The Hidden Ones - Karkh Bureau)
Of Toil and Taxes (Al-Anqa - Karkh Bureau)
The Toll of Greed (Al-Anqa - Karkh Bureau)
Coin, Corruption, and Tea (The Harbourmaster - Karkh Bureau)
A Faceless Feather (The Hidden Ones - Karkh Bureau
Gilded Butterflies (The Treasurer)
Eliminate Al-Pairika in the Bazaar in Karkh and this achievement is yours.
