Wall of Light

Walls of light are electrified entryways created for the purposes of security and quarantine control. Powered by whale oil or windmills, they were primarily deployed in Dunwall at the height of the Rat Plague before being retired, but their use was revived in Karnaca years later under the heavy-handed rule of Duke Luca Abele. Normally, only the City Watch, Grand Guard, and tallboys are able to pass through unharmed, as they deactivate upon their approach. Anyone or anything else attempting passage, including trying to Blink through, will be vaporized.

Sokolov-designed Walls of light as of 1837 work via two electric coils placed together on either side of an entry, as if to resemble a gate. Above these coils is a revolving device that emits a blue light. When a hostile approaches, it will sound an alarm and glow red. It will let out a low-pitched signal when someone attuned to the wall passes through it.

Jindosh Clockworks-designed Walls of light by 1852 function in the same manner, although in lieu of the revolving sensor on top, they appear to have a camera-like device attached to the side which presumably serves the same function.

Upon starting their watch duty, members of the City Watch will be approached by the Technical Officer. This individual will be carrying a device known as a charger, which is attuned to a specific wall of light. Each member of the new shift must lay a hand upon the charger. Once this is done, that wall of light "recognizes" these individuals and will not harm them.

A protagonist can, with the help of rewire tools, reconfigure walls of light to allow them passage. This has the added effect of causing guards to be detected as "unauthorized" users, disintegrating them instantly. The device can also be disabled by removing the whale oil tank or disabling the windmill that powers it. The second tier of Bend Time allows Corvo Attano and Daud to pass through an active wall of light unharmed.

Trivia

 * Rats tend to avoid active walls of light, and if a guard or other hostile notices that a friendly wall of light has been reprogrammed, they will as well. However, if a guard hasn't witnessed someone being disintegrated by the wall, they may attempt to pass it, even if there are other guards throwing stones at it.
 * Bullets, bolts, bottles, and other inanimate objects will also disintegrate when coming in contact with a wall of light.
 * This includes whale oil tanks, meaning that when thrown into a wall of light, they will not explode as they would normally.
 * If a corpse or unconscious body is thrown into the wall, it will also disintegrate.
 * Walls of light drain some of their supply of whale oil every time they incinerate something, and after enough uses, they will shut off.
 * The protagonist can utilize bottles, projectiles, and other objects to deplete a wall of light's whale oil.
 * Once guards notice that a wall has been reprogrammed, they will start throwing rocks at it to drain the wall's supply of whale oil.
 * As guards never make any attempt to replace tanks removed by the protagonist, an unplugged wall will be disabled permanently.
 * In Dishonored 2, guards will notice if a wall of light has been turned off and will begin to search the area.
 * Attacking a wall of light with a sword or gun as "friendlies" attempt to pass through it will activate it and kill them. This can be used to quickly kill entire groups of pursuing guards.
 * If a wolfhound is thrown into a wall of light, the disintegration animation will depict a human foot flying away from it.
 * The practice of "Rat Burning" involves throwing a live rat into a wall of light. Due to the expense of whale oil, this practise is banned.
 * Despite this, City Watch Guards such as Sergeant Heyburn can be seen doing this.
 * The Dishonored achievement Wall of Sparks is granted by killing an enemy with a wall of light.
 * Wall of lights in Dishonored are made by Sokolov Industries, while the ones in Dishonored 2 and Death of the Outsider are made by Jindosh Clockworks. One Sokolov Industries' wall of light can be found in the Royal Conservatory in the mission of the same name.