Nysrock demons are horrid, 14-foot-long cobras with vaguely humanoid faces that protrude from a broad hood. Golden scales run down the length of its snake body to end in a scorpion's stinger that oozes unholy venom. They weigh between 350 and 450 pounds.

Believed to be the offspring of a marilith and a naga, the nysrock is a sinister denizen of the Abyss that is often found in the courts of various demon lords where they serve as advisors and counselors. Their cunning intellects are used to full effect by their masters in weaving battle plans and plots and intrigues against rival lords and enemies.

Rumors abound (supposedly from an eyewitness who lived to tell the tale) of an abyssal plane ruled by a massive nysrock at least 40 feet long. Its palace is a network of underground tunnels populated with all manner of snakes, fiendish serpents, and intelligent and cunning reptiles of all shapes and sizes.