This achievement is gained upon completing the following quests in the Heart of Fear:

The Threshold : Alchemist Gille - A Perfect Potion
The Threshold : Dormir Norval - Dormir's Creation
The Threshold : Alchemist Gille - Dousing the Believers
The Threshold : Anomalous Harbinger - Taking a New Step
The Threshold : a Fear beorthor - Facing Your Fear
The Rebirth: Provisioner Lena - Tentacle Stew
The Rebirth: Barnaby Fellfoot - Cash for Gold
The Rebirth: Falso Fensar - Saving Souls
The Epicenter: Mercenary Hudson - Splitting the Work
The Epicenter: Naju Uddo - Terrifying Taxidermy
The Epicenter: Meps Muddytoe - Encased in Crystal