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"A Divine always has enemies. And Justinia had more than most. I protected her. I watched, had an ear to every door. I identified threats, and I dealt with them."
Left Hand Leliana

Leliana, under the pseudonym of "Sister Nightingale", has served as Left Hand of the Divine under Justinia V and is considered one of the greatest spymasters in Thedas.

The Left Hand of the Divine, or simply the Divine's Left Hand, is an advisor and spymaster to the Divine of the Andrastian Chantry and is charged with gathering intelligence, espionage and assassination from the Grand Cathedral, across most southern nations of Thedas, and other places. During the progressive reign of Divine Justinia V, this position was held by Leliana, an Orlesian bard and veteran of the Fifth Blight that held the title for seven years. She assumed mastery over a coterie of her own agents and provided an effective alternative when diplomacy or blunt force fail, collecting information, dispatching agents and scouts, often signing her letters with an ominous nightingale sigil that leaves no question of its author.

Following Leliana's ascension to Divine Victoria, the office was left vacant.

The Divine's Left Hand's spy network is not the only one that exists. The Qunari use their Ben-Hassrath agents and Viddathari converts to operate as undercover spies to obtain information. Solas himself amassed a large network of spies and agents two years after the Inquisition defeated Corypheus.