Demon's Blood

Source
Quest reward from, the last quest of the main Blasted Lands quest chain.
 * See: Fallen Hero of the Horde for more info.

Trivia
Most probably blood obtained from a cruel demon, Demon's Blood during its time (before TBC) was a fair tank trinket, supplying good resistance, defense, and increase health generation. Normally replaced when the tank would get. Now this trinket is obsolete and the quest chain which is very time consuming and of elite difficulty, is hardly ever done.