Zul'Gurub, home to a vile clan of corrupted trolls. They worship The Blood God, Hakkar. Home to a variety of blood sucking bats, corrupted trolls, even a few giant spiders, Zul'Gurub is ones first step into the raiding arena.
Requiring more strategy than many of even Molten Cores bosses Zul'Gurub can prove to be a fatal step for many beginner guilds, ripping apart unexperienced tanks and healers. Be sure that you can work together as a team before even attempting Zul'Gurub
From the World of Warcraft Site:
Over a thousand years ago the powerful Gurubashi Empire was torn apart by a massive civil war. An influential group of troll priests, known as the Atal'ai, called forth the avatar of an ancient and terrible blood god named Hakkar the Soulflayer.
Though the priests were defeated and ultimately exiled, the great troll empire collapsed upon itself. The exiled priests fled far to the north, into the Swamp of Sorrows, where they erected a great temple to Hakkar in order to prepare for his arrival into the physical world.