Keyholes are located on most doors encountered in the games of Dishonored franchise and can be utilized by the protagonists to scan a room before entering, as well as eavesdropping on any conversations going on inside. This allows a tactical advantage over enemies, as their positions will be known prior to engaging or avoiding them.
This technique is made almost obsolete by Dark Vision, Void Gaze at Tier II and Foresight, as those supernatural abilities allow all enemies to be seen and (with the former two abilities at Tier II) objects within a certain radius, nullifying the advantage gained from peering through keyholes. In Dishonored and its DLCs, keyholes must still be used to eavesdrop on conversations even with Dark Vision or Tier II Void Gaze, while in Dishonored 2 and Death of the Outsider, they can be heard through walls and doors.
Keyholes are most useful when attempting to unlock Mostly Flesh and Steel in Dishonored, and no-power playthrough in Dishonored 2.
- The best way to see Granny Rags talk to her 'little birdies' is by looking through the keyhole of her house leading to the backyard.
- Corvo can occasionally observe members of the City Watch or Overseers peeping through keyholes.
- Sometimes this will even happen while Corvo is on the other side of a keyhole, but he will still remain undetected.
- Some scripted scenes can be activated by looking through keyholes.
- Piero looks at Callista bathing through a keyhole.