Nightingales The Nightingales are a secret inner circle within the Thieves Guild , based in Nightingale Hall . The most recent incarnation of the faction was made up of three elite thieves : Mercer Frey , Karliah , and Gallus Desidenius . The Nightingales exist to protect the shrines of Nocturnal throughout Skyrim . It is common belief that the Nightingales do not exist , and were simply created as a way to scare Footpad s in to doing what they are told . As the Dragonborn progresses through the Thieves Guild , they are invited to join the Nightingales . In doing so , the Dragonborn swears to protect Nocturnal and her shrine , even after death . As a reward for the pledge of service , Nightingales are granted armor blessed by Nocturnal , and receive special powers , including increased luck in their exploits as thieves . After the completion of " Trinity Restored " the Dragonborn becomes a fully - fledged Nightingale . They are then allowed to choose whichever manner of agent of Nocturnal ( see Powers below ) . History . According to " Nightingales : Fact or Fiction ? " , the first signs of the existence of a group dedicated to the service of the Daedric Prince Nocturnal — the Nightingales — surfaced over one - hundred years prior to the events of . A corpse was discovered wearing strange black armor , and bearing an insignia that resembled a nightbird cradling the moon in its wings . Since then , it has always been rumored that a secret inner - circle existed within the Thieves Guild which was responsible for protecting the shrines of Nocturnal . Little is known of the Nightingales ' membership prior to the return of Alduin , but purportedly a Dunmer named Lorthus , who was executed for murder , was suspected of being a Nightingale . Powers . Agents are powers that are gifted from Nocturnal to the Nightingales . There are three known kinds of Agents , each possessing a power that can be used once a day . It is possible to change to another kind of Agent , but only once per day , and only at the Twilight Sepulcher . Agent of Stealth ( crescent moon ) . An Agent of Stealth is an expert infiltrator . They use darkness to conceal themselves . They are granted the power of Shadowcloak of Nocturnal which automatically turns the Nightingale invisible when sneaking . While sneaking , the effect acts as any other form of invisibility , meaning that if the Agent interacts with an object or character , the effect will dissipate . However , the cloak can be re - engaged by leaving and entering sneak again ( as long as the duration holds ) . Shadowcloaks last for two minutes , or indefinitely if the Dragonborn never interacts with anything whilst crouching . Agent of Subterfuge ( half moon ) . An Agent of Subterfuge uses darkness to obscure others ' thoughts and judgement . They are granted the power of Nightingale Subterfuge which forces targets in the area of effect to attack anybody on sight , allowing the Agent to take advantage of the chaos to gain the upper hand . Agent of Strife ( full moon ) . An Agent of Strife uses darkness for their own benefit . They are granted the power of Nightingale Strife that creates a cord between them and their foes . This cord draws health from said foe while giving health to the Agent .