Darkness is a substance featured heavily in Shadows of the DAMNED. Unlike 'normal' darkness encountered in the world of the living, the Darkness in the underworld is a deadly, corrosive force that sucks away the life force of any living creature that enters it.
From the outside, Darkness appears as a thick, dark blue substance with a seemingly jelly-like consistency. As soon as Garcia Hotspur steps into the Darkness his Soul Meter will begin to decrease; once it empties, he will begin to lose health. Exiting the Darkness will fully refill the Soul Meter, but will not recover any lost health. The only things which can dispel the Darkness are Goat Lamps, which can be activated with the Light Shot.
Some areas of Darkness bear no relation whatsoever to the 'real' world, instead taking the form of winding caves or stone platforms that appear to float in an endless void of Darkness. The Darkness is so thick here that it cannot be dispersed, and Garcia must simply sprint through the areas as quickly as possible while collecting Soul Boosters to maintain his Soul Meter. Bizarre things appear in these areas, including giant, mutilated floating heads, an apparition of a semi-naked and gyrating Paula (who can even be walked upon), and Fleming himself.
It is implied that the Darkness is partially sentient to some degree, as shown by the 'hands' that extend from areas of Darkness and try to grab Garcia. These hands first appear in Act 2-1, where they cannot be dodged, and again as a special attack of Fleming's during Act 5-4, where they can be dodged.
Virtually any Demon which enters the Darkness will become coated in thick layer of the substance, which turns it into a Dark Demon. While in this state, Dark Demons are much more aggressive and cannot be harmed by conventional means until the Darkness is removed with the Light Shot. However, the Darkness is instantly fatal to Hammerkop Demons. Some Demons can even generate Darkness themselves, such as Crawler Demons, Darkness Hands and Mikami Heads.