In order to obtain this achievement you must first must find and tag 10 Albino Tarkaas', in which I will provide the areas. Once you find all 10, you must go back to the Camp of the Forgotten and talk to the Ethologist which you can find him and his shop as soon as you enter the camp, from the main gate with the spot lights head left; up the stairs and directly in front of you is his shop. Once all 10 Albino Tarkaas' are found head to his kiosk and buy everything. Once you do the achievement will pop.
ALBINO TARKAAS' LOCATIONS: