This achievement is gained upon collecting the following Overseer Agents.

Ak'Anon Guard
Bandit Lookout
Blighted Scarecrow
Blood Wolf
Cauldron Rat
Crypt Ghoul
Eldritch Wanderer
Faerie Guard
Faerie Royal Guard
Faerie Troublemaker
Faydark Bandit
Faydark Nightgazer
Felwithe Guard
Goblin Grunts
Guardian of the Keep
Kaladim Guard
Kelethin Guard
Koada'Dal Diviner
Masked Changeling
Nightrage Decapitator
Nightrage Narcissist
Orc Legionnaire
Orc Scoutmaster
Pixie Jongleur
Rogue Clockwork
Servant of the Ancients
Shadowmane Brawler
Sleeper's Acolyte
Soul Seductress
Steamwork Shock Trooper
Sylvan Bat
Teir'Dal Marauder
Tormented Dead
Undead Knight
Undertow Skeleton
Werewolf Gypsy

Hidden Steps

• Overseer Unlocked on Server