Liquidark

Liquidark is a mysterious substance in Noctropolis, said to be the distilled liquid essence of darkness. On humans it has phenomenal healing properties, undoing a bullet wound in minutes. It is also said to give the sensation of being so cold it burns.

Liquidark grenades
Darksheer's weapon of choice. Usually carried on his belt, once activated they have a time-delay of a few seconds before they release their payload permeating a location with a cloud of Liquidark absorbing all light, causing utter darkness lasting an indeterminate amount of time. After use they are recharged by immersion in Liquidark.

Trivia

 * There is a strong resemblance to DC Comics character Doctor Mid-Nite's blackout bombs.