Dark Lights are devices used by the Styx to interrogate and control the minds of their victims. They resemble a desk lamp with a flexible stem, on top of which is a dark purple bulb set in a shallow shade. The Dark Light is connected by a cable to a small box with controls. Upon activation, the device vibrates, and the bulb flares a harsh orange before turning an intense purple. The Dark Light uses subsonic technology to disrupt the victim's brain and implant suggestions by the user, creating an unquestioning slave. It is first seen after Will Burrows and Chester Rawls are imprisoned in the Hold shortly after discovering The Colony, where the Styx use it to interrogate both boys.
The victim temporarily loses their sight when the Dark Light is activated, and they feel what is described as an excruciatingly painful spiked ball of energy moving through their body and forcing its way into their skull. Side effects of the Dark Light include nausea, vomiting, loss of conscious, permanent brain damage, memory loss, comas and even heart failure. To date, Celia Burrows is the only person who has resisted a Dark Light even on full power, using meditation techniques she learned in her yoga classes. It took six or seven Dark Lights to interrogate her successfully, and the trauma almost killed her. Although she made a miraculous recovery under the care of the Second Officer and his family, she was permanently blinded. It also gave her the unforeseen ability to control her body temperature, breathing, heart rate and reflexes, and bestowed upon her a powerful olfactory sense that acted as a substitute for her vision.
An offshoot of the Dark Light technology exists as a subsonic aural bomb that can render people and animals immediately unconscious, which was used in Freefall by Oscar Embers and Mrs. Tantrumi to capture Mrs. Burrows and Drake's men as part of a Styx ambush. In Spiral, similar devices are used to prevent inhabitants of the Colony from leaving, and they were also used to deny access to the now vacated Styx Citadel.
The main device with which Darklit victims were cleared was a purger, which Danforth created. Intensive psychological therapy was also required to deprogramme individuals, as Drake demonstrated against Chester's parents, to the point that he threatened to kill their son.
In Mrs Burrow's case, it was her yoga meditation and training that allowed her to bypass the standard effects of a Dark Light.
Will Burrows-he was Darklit in the Hold along with his friend Chester in Tunnels. He survived, but the event caused him to have the urge to jump off high places and kill himself. However, Drake helps him to resist this idea, which the Dark Light implanted. He is cleared by Danforth's Purger in Spiral.
Chester Rawls-he was Darklit in the Hold along with his friend Will in Tunnels. He survived, but became extremely weak afterwards and barely managed through. When on the surface, he uses Danforth's Purger. It is revealed his programming would be to call the Styx and report their location (Parry's mansion).
Dr. Burrows-he was Darklit sometime in the past by the Styx, who wanted him to develop a love for exploration and in the process have Will discover the Colony. In this process, Sarah Jerome would also be led out into the open, like the Styx planned. His programming could be activated when the Styx wanted (in this case, as he began his adventure to the Colony and the Deeps). Since he dies in Closer, he never used the Purger and died Darklit.
Drake -he was Darklit by Eddie back when the Styx forced him to work for them in the Laboratories. Eddie uses this against him in Closer. He is the first to demonstrate the Purger to Will and his friends.
Mrs. Burrows (Part 1) -back when Dr. Burrows was Darklit, Mrs. Burrows was too. Her programming made her the opposite of her husband; she was lazy and spent her days watching TV (Eddie reveals that the Styx did this becuase she had no part to play in their plot). Over the course of the first 3 books, she slowly beats this and goes to help Drake stop the Styx.
Mrs. Burrows (Part 2)-when Drake's plan failed and Mrs. Burrows was captured, she was taken back to the Colony to be Darklit again. However, she was able to resist a battery of 6 Dark Lights using her yoga meditation techniques. This overload causes her to become near-blind and develop her supercharged nose sense.
The Prime Minister -in Closer, Dr. Edward Christopher Darklights the Prime Minister during one of his optometrist appointments. This causes him to shut down the hospitals recieving Elliott's blood (with the Dominion vaccine). He then puts the country under martial law and closes its borders in Spiral. In Terminal, he seems to have beaten this programming, as he is seen talking and planning with Parry on how to stop the Armagi.
Bartleby -while being kept in the Colony in Deeper, he was Darklit by the Rebeccas to attack Will when one of the twins said so. He seems to not be affected by this programming later on in Freefall after he tried to attack Will at Smoking Jean.
Mr. Jeff Rawls and Mrs. Emily Rawls -both of Chester's parents were Darklit sometime during the end of Freefall and the middle of Closer. They were programmed not to recognize their son and call the Styx if he came back to them. Drake has to restrain them and think of a plan to purge them. He almost kills Chester in front of Mr. Rawls, which causes the dad to revert to normal. Drake and Chester repeat the same process on Mrs. Rawls, purging her mind, too. It is revealed Mrs. Rawls would also be used by the Styx to plant a bomb, were it not for Drake's help.
New Germania -after taking the chaparone New Germanian soldiers captive, the Rebeccas and the Styx Darklight them and prepare to Darklight the entire city. Soon the entire city is under Styx control, giving the Styx a huge army for Topsoil invasion.
An Unknown Number of Colonists -during the Phase, the Styx Darklit many residents of the Colony to be used as host bodies for the Warrior Class eggs. Often, the Limiters took a Colonist at gunpoint, brought them up Topsoil to the Phase Factory, and Darklit them to a near-dead state.
An Unknown Number of Topsoilers -the Styx have many people in the government, military, and media, and it can be guessed that a portion of these have been Darklit. Also, during the Phase, the Styx Darklit many Topsoil civilians as hosts.
- Each Dark Light has four small cylinder-shaped tubes in its base. When activated, the tubes emit wavelengths that are very specific, giving each Dark Light a specific 'signature.'