This achievement is gained upon completing the following quests in Combine Dredge

Praetor Lutgardis - Doomscale Captives
Captain Mewes - The Pirate and the Pea
Captain Mewes - Undermining the Mining
Captain Mewes - Research Wrecks
a Kedge Spectator - Cracking the Shell
a Kedge Spectator - Plucking the Eyes
a Kedge Spectator - Snuffing the Life
a Kedge Spectator - Armored Extremists
a Kedge Spectator - Quelling the Rage
a Kedge Spectator - Ending Their Work
a Kedge Spectator - Finishing the Cult
a scurvy mariner - Scurvy Vengeance
a scurvy mariner - Creepy Crab Masters
Aqusos Ulto - Kedge Counterblow